- ASP.NET Interview Questions Part 1
- ASP.NET Interview Questions Part 2
- ASP.NET Interview Questions Part 3
- ASP.NET Interview Questions Part 4
- ASP.NET Interview Questions Part 5
- ASP.NET Interview Questions Part 6
- ASP.NET Interview Questions Part 7
- ASP.NET Interview Questions Part 8
- ASP.NET Interview Questions Part 9
- ASP.NET Interview Questions Part 10
- ASP.NET Interview Questions Part 11
- ASP.NET Interview Questions Part 12
- ASP.NET Interview Questions Part 13
- ASP.NET Interview Questions Part 14
- ASP.NET Interview Questions Part 15
Showing posts with label ASP.net interview questions. Show all posts
Showing posts with label ASP.net interview questions. Show all posts
Wednesday, April 23, 2008
asp.net interview questions list
Here is the list of asp.net interview questions on Interview Helper website:
Sunday, January 20, 2008
SQL Admin Interview Questions
1. Explain the architecture of SQL Server?
**
2. Different types of Backups?
o A full database backup is a full copy of the database.
o A transaction log backup copies only the transaction log.
o A differential backup copies only the database pages modified after the last full database backup.
o A file or filegroup restore allows the recovery of just the portion of a database that was on the failed disk.
3. What are ‘jobs’ in SQL Server? How do we create one? What is tasks?
Using SQL Server Agent jobs, you can automate administrative tasks and run them on a recurring basis.
**
4. What is database replication? What are the different types of replication you can set up in SQL Server? How are they used? What is snapshot replication how is it different from Transactional replication?
Replication is the process of copying/moving data between databases on the same or different servers. SQL Server supports the following types of replication scenarios:
1. Snapshot replication - It distributes data exactly as it appears at a specific moment in time and doesn’t monitor for updates. It can be used when data changes are infrequent. It is often used for browsing data such as price lists, online catalog, or data for decision support where the current data is not required and data is used as read only.
2. Transactional replication (with immediate updating subscribers, with queued updating subscribers) - With this an initial snapshot of data is applied, and whenever data modifications are made at the publisher, the individual transactions are captured and propagated to the subscribers.
3. Merge replication - It is the process of distributing the data between publisher and subscriber, it allows the publisher and subscriber to update the data while connected or disconnected, and then merging the updates between the sites when they are connected.
5. How can u look at what are the process running on SQL server? How can you kill a process in SQL server?
o Expand a server group, and then expand a server.
o Expand Management, and then expand Current Activity.
o Click Process Info. The current server activity is displayed in the details pane.
In the details pane, right-click a Process ID, and then click Kill Process.
6. What is RAID and what are different types of RAID configurations?
RAID stands for Redundant Array of Inexpensive Disks, used to provide fault tolerance to database servers. There are six RAID levels 0 through 5 offering different levels of performance, fault tolerance.
7.
Some of the tools/ways that help you troubleshooting performance problems are: SET SHOWPLAN_ALL ON, SET SHOWPLAN_TEXT ON, SET STATISTICS IO ON, SQL Server Profiler, Windows NT /2000 Performance monitor, Graphical execution plan in Query Analyzer.
8. How to determine the service pack currently installed on SQL Server?
The global variable @@Version stores the build number of the sqlservr.exe, which is used to determine the service pack installed.
eg: Microsoft SQL Server 2000 - 8.00.760 (Intel X86) Dec 17 2002 14:22:05 Copyright (c) 1988-2003 Microsoft Corporation Enterprise Edition on Windows NT 5.0 (Build 2195: Service Pack 3)
9. What is the purpose of using COLLATE in a query?
The term, collation, refers to a set of rules that determine how data is sorted and compared. In Microsoft® SQL Server 2000, it is not required to separately specify code page and sort order for character data, and the collation used for Unicode data. Instead, specify the collation name and sorting rules to use. Character data is sorted using rules that define the correct character sequence, with options for specifying case-sensitivity, accent marks, kana character types, and character width. Microsoft SQL Server 2000 collations include these groupings:
• Windows collations - Windows collations define rules for storing character data based on the rules defined for an associated Windows locale. The base Windows collation rules specify which alphabet or language is used when dictionary sorting is applied, as well as the code page used to store non-Unicode character data. For Windows collations, the nchar, nvarchar, and ntext data types have the same sorting behavior as char, varchar, and text data types
• SQL collations - SQL collations are provided for compatibility with sort orders in earlier versions of Microsoft SQL Server.
Sort Order
Binary is the fastest sorting order, and is case-sensitive. If Binary is selected, the Case-sensitive, Accent-sensitive, Kana-sensitive, and Width-sensitive options are not available.
Sort order Description
Binary Sorts and compares data in Microsoft® SQL Server™ tables based on the bit patterns defined for each character. Binary sort order is case-sensitive, that is lowercase precedes uppercase, and accent-sensitive. This is the fastest sorting order.
If this option is not selected, SQL Server follows sorting and comparison rules as defined in dictionaries for the associated language or alphabet.
Case-sensitive Specifies that SQL Server distinguish between uppercase and lowercase letters.
If not selected, SQL Server considers the uppercase and lowercase versions of letters to be equal. SQL Server does not define whether lowercase letters sort lower or higher in relation to uppercase letters when Case-sensitive is not selected.
Accent-sensitive Specifies that SQL Server distinguish between accented and unaccented characters. For example, 'a' is not equal to 'รก'.
If not selected, SQL Server considers the accented and unaccented versions of letters to be equal.
Kana-sensitive Specifies that SQL Server distinguish between the two types of Japanese kana characters: Hiragana and Katakana.
If not selected, SQL Server considers Hiragana and Katakana characters to be equal.
Width-sensitive Specifies that SQL Server distinguish between a single-byte character (half-width) and the same character when represented as a double-byte character (full-width).
If not selected, SQL Server considers the single-byte and double-byte representation of the same character to be equal.
Windows collation options:
• Use Latin1_General for the U.S. English character set (code page 1252).
• Use Modern_Spanish for all variations of Spanish, which also use the same character set as U.S. English (code page 1252).
• Use Arabic for all variations of Arabic, which use the Arabic character set (code page 1256).
• Use Japanese_Unicode for the Unicode version of Japanese (code page 932), which has a different sort order from Japanese, but the same code page (932).
10. What is the STUFF Function and how does it differ from the REPLACE function?
STUFF - Deletes a specified length of characters and inserts another set of characters at a specified starting point.
SELECT STUFF('abcdef', 2, 3, 'ijklmn')
GO
Here is the result set:
---------
aijklmnef
REPLACE - Replaces all occurrences of the second given string expression in the first string expression with a third expression.
SELECT REPLACE('abcdefghicde','cde','xxx')
GO
Here is the result set:
------------
abxxxfghixxx
11. What does it mean to have quoted_identifier on? What are the implications of having it off?
When SET QUOTED_IDENTIFIER is OFF (default), literal strings in expressions can be delimited by single or double quotation marks.
When SET QUOTED_IDENTIFIER is ON, all strings delimited by double quotation marks are interpreted as object identifiers. Therefore, quoted identifiers do not have to follow the Transact-SQL rules for identifiers.
SET QUOTED_IDENTIFIER must be ON when creating or manipulating indexes on computed columns or indexed views. If SET QUOTED_IDENTIFIER is OFF, CREATE, UPDATE, INSERT, and DELETE statements on tables with indexes on computed columns or indexed views will fail.
The SQL Server ODBC driver and Microsoft OLE DB Provider for SQL Server automatically set QUOTED_IDENTIFIER to ON when connecting.
When a stored procedure is created, the SET QUOTED_IDENTIFIER and SET ANSI_NULLS settings are captured and used for subsequent invocations of that stored procedure. When executed inside a stored procedure, the setting of SET QUOTED_IDENTIFIER is not changed.
SET QUOTED_IDENTIFIER OFF
GO
-- Attempt to create a table with a reserved keyword as a name
-- should fail.
CREATE TABLE "select" ("identity" int IDENTITY, "order" int)
GO
SET QUOTED_IDENTIFIER ON
GO
-- Will succeed.
CREATE TABLE "select" ("identity" int IDENTITY, "order" int)
GO
12. What is the purpose of UPDATE STATISTICS?
Updates information about the distribution of key values for one or more statistics groups (collections) in the specified table or indexed view.
13. Fundamentals of Data warehousing & olap?
14. What do u mean by OLAP server? What is the difference between OLAP and OLTP?
15. What is a tuple?
A tuple is an instance of data within a relational database.
16. Services and user Accounts maintenance
17. sp_configure commands?
Displays or changes global configuration settings for the current server.
18. What is the basic functions for master, msdb, tempdb databases?
Microsoft® SQL Server 2000 systems have four system databases:
• master - The master database records all of the system level information for a SQL Server system. It records all login accounts and all system configuration settings. master is the database that records the existence of all other databases, including the location of the database files.
• tempdb - tempdb holds all temporary tables and temporary stored procedures. It also fills any other temporary storage needs such as work tables generated by SQL Server. tempdb is re-created every time SQL Server is started so the system starts with a clean copy of the database.
By default, tempdb autogrows as needed while SQL Server is running. If the size defined for tempdb is small, part of your system processing load may be taken up with autogrowing tempdb to the size needed to support your workload each time to restart SQL Server. You can avoid this overhead by using ALTER DATABASE to increase the size of tempdb.
• model - The model database is used as the template for all databases created on a system. When a CREATE DATABASE statement is issued, the first part of the database is created by copying in the contents of the model database, then the remainder of the new database is filled with empty pages. Because tempdb is created every time SQL Server is started, the model database must always exist on a SQL Server system.
• msdb - The msdb database is used by SQL Server Agent for scheduling alerts and jobs, and recording operators.
19. What are sequence diagrams? What you will get out of this sequence diagrams?
Sequence diagrams document the interactions between classes to achieve a result, such as a use case. Because UML is designed for object-oriented programming, these communications between classes are known as messages. The sequence diagram lists objects horizontally, and time vertically, and models these messages over time.
20. What are the new features of SQL 2000 than SQL 7? What are the new datatypes in sql?
• XML Support - The relational database engine can return data as Extensible Markup Language (XML) documents. Additionally, XML can also be used to insert, update, and delete values in the database. (for xml raw - to retrieve output as xml type)
• User-Defined Functions - The programmability of Transact-SQL can be extended by creating your own Transact-SQL functions. A user-defined function can return either a scalar value or a table.
• Indexed Views - Indexed views can significantly improve the performance of an application where queries frequently perform certain joins or aggregations. An indexed view allows indexes to be created on views, where the result set of the view is stored and indexed in the database.
• New Data Types - SQL Server 2000 introduces three new data types. bigint is an 8-byte integer type. sql_variant is a type that allows the storage of data values of different data types. table is a type that allows applications to store results temporarily for later use. It is supported for variables, and as the return type for user-defined functions.
• INSTEAD OF and AFTER Triggers - INSTEAD OF triggers are executed instead of the triggering action (for example, INSERT, UPDATE, DELETE). They can also be defined on views, in which case they greatly extend the types of updates a view can support. AFTER triggers fire after the triggering action. SQL Server 2000 introduces the ability to specify which AFTER triggers fire first and last.
• Multiple Instances of SQL Server - SQL Server 2000 supports running multiple instances of the relational database engine on the same computer. Each computer can run one instance of the relational database engine from SQL Server version 6.5 or 7.0, along with one or more instances of the database engine from SQL Server 2000. Each instance has its own set of system and user databases.
• Index Enhancements - You can now create indexes on computed columns. You can specify whether indexes are built in ascending or descending order, and if the database engine should use parallel scanning and sorting during index creation.
21. How do we open SQL Server in single user mode?
We can accomplish this in any of the three ways given below :-
. From Command Prompt :-
sqlservr -m
a. From Startup Options :-
Go to SQL Server Properties by right-clicking on the Server name in the Enterprise manager.
Under the 'General' tab, click on 'Startup Parameters'.
Enter a value of -m in the Parameter.
b. From Registry :-
Go to HKEY_LOCAL_MACHINE\Software\Microsoft\MSSQLServer\MSSQLServer\Parameters.
Add new string value.
Specify the 'Name' as SQLArg(n) & 'Data' as -m.
Where n is the argument number in the list of arguments.
22. Difference between clustering and NLB (Network Load Balancing)?
**
23. Explain Active/Active and Active/Passive cluster configurations?
**
24. What is Log Shipping?
In Microsoft® SQL Server™ 2000 Enterprise Edition, you can use log shipping to feed transaction logs from one database to another on a constant basis. Continually backing up the transaction logs from a source database and then copying and restoring the logs to a destination database keeps the destination database synchronized with the source database. This allows you to have a backup server and also provides a way to offload query processing from the main computer (the source server) to read-only destination servers.
25. What are the main steps you take care for enhancing SQL Server performance?
**
26. You have to check whether any users are connected to sql server database and if any user is connected to database, you have to disconnect the user(s) and run a process in a job. How do you do the above in a job?
**
XML
27. How can I convert data in a Microsoft Access table into XML format?
The following applications can help you convert Access data into XML format: Access 2002, ADO 2.5, and SQLXML. Access 2002 (part of Microsoft Office XP) enables you to query or save a table in XML format. You might be able to automate this process. ADO 2.5 and later enables you to open the data into a recordset, then persist the recordset in XML format, as the following code shows:
rs.Save "c:\rs.xml", adPersistXML
You can use linked servers to add the Access database to your SQL Server 2000 database so you can run queries from within SQL Server to retrieve data. Then, through HTTP, you can use the SQLXML technology to extract the Access data in the XML format you want.
NEW
28. @@IDENTITY ?
Ans: Returns the last-inserted identity value.
29. If a job is fail in sql server, how do find what went wrong?
30. Have you used Error handling in DTS?
**
2. Different types of Backups?
o A full database backup is a full copy of the database.
o A transaction log backup copies only the transaction log.
o A differential backup copies only the database pages modified after the last full database backup.
o A file or filegroup restore allows the recovery of just the portion of a database that was on the failed disk.
3. What are ‘jobs’ in SQL Server? How do we create one? What is tasks?
Using SQL Server Agent jobs, you can automate administrative tasks and run them on a recurring basis.
**
4. What is database replication? What are the different types of replication you can set up in SQL Server? How are they used? What is snapshot replication how is it different from Transactional replication?
Replication is the process of copying/moving data between databases on the same or different servers. SQL Server supports the following types of replication scenarios:
1. Snapshot replication - It distributes data exactly as it appears at a specific moment in time and doesn’t monitor for updates. It can be used when data changes are infrequent. It is often used for browsing data such as price lists, online catalog, or data for decision support where the current data is not required and data is used as read only.
2. Transactional replication (with immediate updating subscribers, with queued updating subscribers) - With this an initial snapshot of data is applied, and whenever data modifications are made at the publisher, the individual transactions are captured and propagated to the subscribers.
3. Merge replication - It is the process of distributing the data between publisher and subscriber, it allows the publisher and subscriber to update the data while connected or disconnected, and then merging the updates between the sites when they are connected.
5. How can u look at what are the process running on SQL server? How can you kill a process in SQL server?
o Expand a server group, and then expand a server.
o Expand Management, and then expand Current Activity.
o Click Process Info. The current server activity is displayed in the details pane.
In the details pane, right-click a Process ID, and then click Kill Process.
6. What is RAID and what are different types of RAID configurations?
RAID stands for Redundant Array of Inexpensive Disks, used to provide fault tolerance to database servers. There are six RAID levels 0 through 5 offering different levels of performance, fault tolerance.
7.
Some of the tools/ways that help you troubleshooting performance problems are: SET SHOWPLAN_ALL ON, SET SHOWPLAN_TEXT ON, SET STATISTICS IO ON, SQL Server Profiler, Windows NT /2000 Performance monitor, Graphical execution plan in Query Analyzer.
8. How to determine the service pack currently installed on SQL Server?
The global variable @@Version stores the build number of the sqlservr.exe, which is used to determine the service pack installed.
eg: Microsoft SQL Server 2000 - 8.00.760 (Intel X86) Dec 17 2002 14:22:05 Copyright (c) 1988-2003 Microsoft Corporation Enterprise Edition on Windows NT 5.0 (Build 2195: Service Pack 3)
9. What is the purpose of using COLLATE in a query?
The term, collation, refers to a set of rules that determine how data is sorted and compared. In Microsoft® SQL Server 2000, it is not required to separately specify code page and sort order for character data, and the collation used for Unicode data. Instead, specify the collation name and sorting rules to use. Character data is sorted using rules that define the correct character sequence, with options for specifying case-sensitivity, accent marks, kana character types, and character width. Microsoft SQL Server 2000 collations include these groupings:
• Windows collations - Windows collations define rules for storing character data based on the rules defined for an associated Windows locale. The base Windows collation rules specify which alphabet or language is used when dictionary sorting is applied, as well as the code page used to store non-Unicode character data. For Windows collations, the nchar, nvarchar, and ntext data types have the same sorting behavior as char, varchar, and text data types
• SQL collations - SQL collations are provided for compatibility with sort orders in earlier versions of Microsoft SQL Server.
Sort Order
Binary is the fastest sorting order, and is case-sensitive. If Binary is selected, the Case-sensitive, Accent-sensitive, Kana-sensitive, and Width-sensitive options are not available.
Sort order Description
Binary Sorts and compares data in Microsoft® SQL Server™ tables based on the bit patterns defined for each character. Binary sort order is case-sensitive, that is lowercase precedes uppercase, and accent-sensitive. This is the fastest sorting order.
If this option is not selected, SQL Server follows sorting and comparison rules as defined in dictionaries for the associated language or alphabet.
Case-sensitive Specifies that SQL Server distinguish between uppercase and lowercase letters.
If not selected, SQL Server considers the uppercase and lowercase versions of letters to be equal. SQL Server does not define whether lowercase letters sort lower or higher in relation to uppercase letters when Case-sensitive is not selected.
Accent-sensitive Specifies that SQL Server distinguish between accented and unaccented characters. For example, 'a' is not equal to 'รก'.
If not selected, SQL Server considers the accented and unaccented versions of letters to be equal.
Kana-sensitive Specifies that SQL Server distinguish between the two types of Japanese kana characters: Hiragana and Katakana.
If not selected, SQL Server considers Hiragana and Katakana characters to be equal.
Width-sensitive Specifies that SQL Server distinguish between a single-byte character (half-width) and the same character when represented as a double-byte character (full-width).
If not selected, SQL Server considers the single-byte and double-byte representation of the same character to be equal.
Windows collation options:
• Use Latin1_General for the U.S. English character set (code page 1252).
• Use Modern_Spanish for all variations of Spanish, which also use the same character set as U.S. English (code page 1252).
• Use Arabic for all variations of Arabic, which use the Arabic character set (code page 1256).
• Use Japanese_Unicode for the Unicode version of Japanese (code page 932), which has a different sort order from Japanese, but the same code page (932).
10. What is the STUFF Function and how does it differ from the REPLACE function?
STUFF - Deletes a specified length of characters and inserts another set of characters at a specified starting point.
SELECT STUFF('abcdef', 2, 3, 'ijklmn')
GO
Here is the result set:
---------
aijklmnef
REPLACE - Replaces all occurrences of the second given string expression in the first string expression with a third expression.
SELECT REPLACE('abcdefghicde','cde','xxx')
GO
Here is the result set:
------------
abxxxfghixxx
11. What does it mean to have quoted_identifier on? What are the implications of having it off?
When SET QUOTED_IDENTIFIER is OFF (default), literal strings in expressions can be delimited by single or double quotation marks.
When SET QUOTED_IDENTIFIER is ON, all strings delimited by double quotation marks are interpreted as object identifiers. Therefore, quoted identifiers do not have to follow the Transact-SQL rules for identifiers.
SET QUOTED_IDENTIFIER must be ON when creating or manipulating indexes on computed columns or indexed views. If SET QUOTED_IDENTIFIER is OFF, CREATE, UPDATE, INSERT, and DELETE statements on tables with indexes on computed columns or indexed views will fail.
The SQL Server ODBC driver and Microsoft OLE DB Provider for SQL Server automatically set QUOTED_IDENTIFIER to ON when connecting.
When a stored procedure is created, the SET QUOTED_IDENTIFIER and SET ANSI_NULLS settings are captured and used for subsequent invocations of that stored procedure. When executed inside a stored procedure, the setting of SET QUOTED_IDENTIFIER is not changed.
SET QUOTED_IDENTIFIER OFF
GO
-- Attempt to create a table with a reserved keyword as a name
-- should fail.
CREATE TABLE "select" ("identity" int IDENTITY, "order" int)
GO
SET QUOTED_IDENTIFIER ON
GO
-- Will succeed.
CREATE TABLE "select" ("identity" int IDENTITY, "order" int)
GO
12. What is the purpose of UPDATE STATISTICS?
Updates information about the distribution of key values for one or more statistics groups (collections) in the specified table or indexed view.
13. Fundamentals of Data warehousing & olap?
14. What do u mean by OLAP server? What is the difference between OLAP and OLTP?
15. What is a tuple?
A tuple is an instance of data within a relational database.
16. Services and user Accounts maintenance
17. sp_configure commands?
Displays or changes global configuration settings for the current server.
18. What is the basic functions for master, msdb, tempdb databases?
Microsoft® SQL Server 2000 systems have four system databases:
• master - The master database records all of the system level information for a SQL Server system. It records all login accounts and all system configuration settings. master is the database that records the existence of all other databases, including the location of the database files.
• tempdb - tempdb holds all temporary tables and temporary stored procedures. It also fills any other temporary storage needs such as work tables generated by SQL Server. tempdb is re-created every time SQL Server is started so the system starts with a clean copy of the database.
By default, tempdb autogrows as needed while SQL Server is running. If the size defined for tempdb is small, part of your system processing load may be taken up with autogrowing tempdb to the size needed to support your workload each time to restart SQL Server. You can avoid this overhead by using ALTER DATABASE to increase the size of tempdb.
• model - The model database is used as the template for all databases created on a system. When a CREATE DATABASE statement is issued, the first part of the database is created by copying in the contents of the model database, then the remainder of the new database is filled with empty pages. Because tempdb is created every time SQL Server is started, the model database must always exist on a SQL Server system.
• msdb - The msdb database is used by SQL Server Agent for scheduling alerts and jobs, and recording operators.
19. What are sequence diagrams? What you will get out of this sequence diagrams?
Sequence diagrams document the interactions between classes to achieve a result, such as a use case. Because UML is designed for object-oriented programming, these communications between classes are known as messages. The sequence diagram lists objects horizontally, and time vertically, and models these messages over time.
20. What are the new features of SQL 2000 than SQL 7? What are the new datatypes in sql?
• XML Support - The relational database engine can return data as Extensible Markup Language (XML) documents. Additionally, XML can also be used to insert, update, and delete values in the database. (for xml raw - to retrieve output as xml type)
• User-Defined Functions - The programmability of Transact-SQL can be extended by creating your own Transact-SQL functions. A user-defined function can return either a scalar value or a table.
• Indexed Views - Indexed views can significantly improve the performance of an application where queries frequently perform certain joins or aggregations. An indexed view allows indexes to be created on views, where the result set of the view is stored and indexed in the database.
• New Data Types - SQL Server 2000 introduces three new data types. bigint is an 8-byte integer type. sql_variant is a type that allows the storage of data values of different data types. table is a type that allows applications to store results temporarily for later use. It is supported for variables, and as the return type for user-defined functions.
• INSTEAD OF and AFTER Triggers - INSTEAD OF triggers are executed instead of the triggering action (for example, INSERT, UPDATE, DELETE). They can also be defined on views, in which case they greatly extend the types of updates a view can support. AFTER triggers fire after the triggering action. SQL Server 2000 introduces the ability to specify which AFTER triggers fire first and last.
• Multiple Instances of SQL Server - SQL Server 2000 supports running multiple instances of the relational database engine on the same computer. Each computer can run one instance of the relational database engine from SQL Server version 6.5 or 7.0, along with one or more instances of the database engine from SQL Server 2000. Each instance has its own set of system and user databases.
• Index Enhancements - You can now create indexes on computed columns. You can specify whether indexes are built in ascending or descending order, and if the database engine should use parallel scanning and sorting during index creation.
21. How do we open SQL Server in single user mode?
We can accomplish this in any of the three ways given below :-
. From Command Prompt :-
sqlservr -m
a. From Startup Options :-
Go to SQL Server Properties by right-clicking on the Server name in the Enterprise manager.
Under the 'General' tab, click on 'Startup Parameters'.
Enter a value of -m in the Parameter.
b. From Registry :-
Go to HKEY_LOCAL_MACHINE\Software\Microsoft\MSSQLServer\MSSQLServer\Parameters.
Add new string value.
Specify the 'Name' as SQLArg(n) & 'Data' as -m.
Where n is the argument number in the list of arguments.
22. Difference between clustering and NLB (Network Load Balancing)?
**
23. Explain Active/Active and Active/Passive cluster configurations?
**
24. What is Log Shipping?
In Microsoft® SQL Server™ 2000 Enterprise Edition, you can use log shipping to feed transaction logs from one database to another on a constant basis. Continually backing up the transaction logs from a source database and then copying and restoring the logs to a destination database keeps the destination database synchronized with the source database. This allows you to have a backup server and also provides a way to offload query processing from the main computer (the source server) to read-only destination servers.
25. What are the main steps you take care for enhancing SQL Server performance?
**
26. You have to check whether any users are connected to sql server database and if any user is connected to database, you have to disconnect the user(s) and run a process in a job. How do you do the above in a job?
**
XML
27. How can I convert data in a Microsoft Access table into XML format?
The following applications can help you convert Access data into XML format: Access 2002, ADO 2.5, and SQLXML. Access 2002 (part of Microsoft Office XP) enables you to query or save a table in XML format. You might be able to automate this process. ADO 2.5 and later enables you to open the data into a recordset, then persist the recordset in XML format, as the following code shows:
rs.Save "c:\rs.xml", adPersistXML
You can use linked servers to add the Access database to your SQL Server 2000 database so you can run queries from within SQL Server to retrieve data. Then, through HTTP, you can use the SQLXML technology to extract the Access data in the XML format you want.
NEW
28. @@IDENTITY ?
Ans: Returns the last-inserted identity value.
29. If a job is fail in sql server, how do find what went wrong?
30. Have you used Error handling in DTS?
IIS Interview Questions
1. In which process does IIS runs (was asking about the EXE file)
inetinfo.exe is the Microsoft IIS server running, handling ASP.NET requests among other things. When an ASP.NET request is received (usually a file with .aspx extension), the ISAPI filter aspnet_isapi.dll takes care of it by passing the request to the actual worker process aspnet_wp.exe.
2. Where are the IIS log files stored?
C:\WINDOWS\system32\Logfiles\W3SVC1
OR
c:\winnt\system32\LogFiles\W3SVC1
3. What are the different IIS authentication modes in IIS 5.0 and Explain? Difference between basic and digest authentication modes?
IIS provides a variety of authentication schemes:
• Anonymous (enabled by default)
• Basic
• Digest
• Integrated Windows authentication (enabled by default)
• Client Certificate Mapping
Anonymous
Anonymous authentication gives users access to the public areas of your Web site without prompting them for a user name or password. Although listed as an authentication scheme, it is not technically performing any client authentication because the client is not required to supply any credentials. Instead, IIS provides stored credentials to Windows using a special user account, IUSR_machinename. By default, IIS controls the password for this account. Whether or not IIS controls the password affects the permissions the anonymous user has. When IIS controls the password, a sub authentication DLL (iissuba.dll) authenticates the user using a network logon. The function of this DLL is to validate the password supplied by IIS and to inform Windows that the password is valid, thereby authenticating the client. However, it does not actually provide a password to Windows. When IIS does not control the password, IIS calls the LogonUser() API in Windows and provides the account name, password and domain name to log on the user using a local logon. After the logon, IIS caches the security token and impersonates the account. A local logon makes it possible for the anonymous user to access network resources, whereas a network logon does not.
Basic Authentication
IIS Basic authentication as an implementation of the basic authentication scheme found in section 11 of the HTTP 1.0 specification.
As the specification makes clear, this method is, in and of itself, non-secure. The reason is that Basic authentication assumes a trusted connection between client and server. Thus, the username and password are transmitted in clear text. More specifically, they are transmitted using Base64 encoding, which is trivially easy to decode. This makes Basic authentication the wrong choice to use over a public network on its own.
Basic Authentication is a long-standing standard supported by nearly all browsers. It also imposes no special requirements on the server side -- users can authenticate against any NT domain, or even against accounts on the local machine. With SSL to shelter the security credentials while they are in transmission, you have an authentication solution that is both highly secure and quite flexible.
Digest Authentication
The Digest authentication option was added in Windows 2000 and IIS 5.0. Like Basic authentication, this is an implementation of a technique suggested by Web standards, namely RFC 2069 (superceded by RFC 2617).
Digest authentication also uses a challenge/response model, but it is much more secure than Basic authentication (when used without SSL). It achieves this greater security not by encrypting the secret (the password) before sending it, but rather by following a different design pattern -- one that does not require the client to transmit the password over the wire at all.
Instead of sending the password itself, the client transmits a one-way message digest (a checksum) of the user's password, using (by default) the MD5 algorithm. The server then fetches the password for that user from a Windows 2000 Domain Controller, reruns the checksum algorithm on it, and compares the two digests. If they match, the server knows that the client knows the correct password, even though the password itself was never sent. (If you have ever wondered what the default ISAPI filter "md5filt" that is installed with IIS 5.0 is used for, now you know.
Integrated Windows Authentication
Integrated Windows authentication (formerly known as NTLM authentication and Windows NT Challenge/Response authentication) can use either NTLM or Kerberos V5 authentication and only works with Internet Explorer 2.0 and later.
When Internet Explorer attempts to access a protected resource, IIS sends two WWW-Authenticate headers, Negotiate and NTLM.
• If Internet Explorer recognizes the Negotiate header, it will choose it because it is listed first. When using Negotiate, the browser will return information for both NTLM and Kerberos. At the server, IIS will use Kerberos if both the client (Internet Explorer 5.0 and later) and server (IIS 5.0 and later) are running Windows 2000 and later, and both are members of the same domain or trusted domains. Otherwise, the server will default to using NTLM.
• If Internet Explorer does not understand Negotiate, it will use NTLM.
So, which mechanism is used depends upon a negotiation between Internet Explorer and IIS.
When used in conjunction with Kerberos v5 authentication, IIS can delegate security credentials among computers running Windows 2000 and later that are trusted and configured for delegation. Delegation enables remote access of resources on behalf of the delegated user.
Integrated Windows authentication is the best authentication scheme in an intranet environment where users have Windows domain accounts, especially when using Kerberos. Integrated Windows authentication, like digest authentication, does not pass the user's password across the network. Instead, a hashed value is exchanged.
Client Certificate Mapping
A certificate is a digitally signed statement that contains information about an entity and the entity's public key, thus binding these two pieces of information together. A trusted organization (or entity) called a Certification Authority (CA) issues a certificate after the CA verifies that the entity is who it says it is. Certificates can contain different types of data. For example, an X.509 certificate includes the format of the certificate, the serial number of the certificate, the algorithm used to sign the certificate, the name of the CA that issued the certificate, the name and public key of the entity requesting the certificate, and the CA's signature. X.509 client certificates simplify authentication for larger user bases because they do not rely on a centralized account database. You can verify a certificate simply by examining the certificate.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vsent7/html/vxconIISAuthentication.asp
4. How to configure the sites in Web server (IIS)?
5. Advantages in IIS 6.0?
http://www.microsoft.com/windowsserver2003/iis/evaluation/features/default.mspx
http://www.microsoft.com/technet/treeview/default.asp?url=/technet/prodtechnol/windowsserver2003/proddocs/datacenter/gs_whatschanged.asp
6. IIS Isolation Levels?
Internet Information Server introduced the notion "Isolation Level", which is also present in IIS4 under a different name. IIS5 supports three isolation levels, that you can set from the Home Directory tab of the site's Properties dialog:
• Low (IIS Process): ASP pages run in INetInfo.Exe, the main IIS process, therefore they are executed in-process. This is the fastest setting, and is the default under IIS4. The problem is that if ASP crashes, IIS crashes as well and must be restarted (IIS5 has a reliable restart feature that automatically restarts a server when a fatal error occurs).
• Medium (Pooled): In this case ASP runs in a different process, which makes this setting more reliable: if ASP crashes IIS won't. All the ASP applications at the Medium isolation level share the same process, so you can have a web site running with just two processes (IIS and ASP process). IIS5 is the first Internet Information Server version that supports this setting, which is also the default setting when you create an IIS5 application. Note that an ASP application that runs at this level is run under COM+, so it's hosted in DLLHOST.EXE (and you can see this executable in the Task Manager).
• High (Isolated): Each ASP application runs out-process in its own process space, therefore if an ASP application crashes, neither IIS nor any other ASP application will be affected. The downside is that you consume more memory and resources if the server hosts many ASP applications. Both IIS4 and IIS5 supports this setting: under IIS4 this process runs inside MTS.EXE, while under IIS5 it runs inside DLLHOST.EXE.
When selecting an isolation level for your ASP application, keep in mind that out-process settings - that is, Medium and High - are less efficient than in-process (Low). However, out-process communication has been vastly improved under IIS5, and in fact IIS5's Medium isolation level often deliver better results than IIS4's Low isolation. In practice, you shouldn't set the Low isolation level for an IIS5 application unless you really need to serve hundreds pages per second.
inetinfo.exe is the Microsoft IIS server running, handling ASP.NET requests among other things. When an ASP.NET request is received (usually a file with .aspx extension), the ISAPI filter aspnet_isapi.dll takes care of it by passing the request to the actual worker process aspnet_wp.exe.
2. Where are the IIS log files stored?
C:\WINDOWS\system32\Logfiles\W3SVC1
OR
c:\winnt\system32\LogFiles\W3SVC1
3. What are the different IIS authentication modes in IIS 5.0 and Explain? Difference between basic and digest authentication modes?
IIS provides a variety of authentication schemes:
• Anonymous (enabled by default)
• Basic
• Digest
• Integrated Windows authentication (enabled by default)
• Client Certificate Mapping
Anonymous
Anonymous authentication gives users access to the public areas of your Web site without prompting them for a user name or password. Although listed as an authentication scheme, it is not technically performing any client authentication because the client is not required to supply any credentials. Instead, IIS provides stored credentials to Windows using a special user account, IUSR_machinename. By default, IIS controls the password for this account. Whether or not IIS controls the password affects the permissions the anonymous user has. When IIS controls the password, a sub authentication DLL (iissuba.dll) authenticates the user using a network logon. The function of this DLL is to validate the password supplied by IIS and to inform Windows that the password is valid, thereby authenticating the client. However, it does not actually provide a password to Windows. When IIS does not control the password, IIS calls the LogonUser() API in Windows and provides the account name, password and domain name to log on the user using a local logon. After the logon, IIS caches the security token and impersonates the account. A local logon makes it possible for the anonymous user to access network resources, whereas a network logon does not.
Basic Authentication
IIS Basic authentication as an implementation of the basic authentication scheme found in section 11 of the HTTP 1.0 specification.
As the specification makes clear, this method is, in and of itself, non-secure. The reason is that Basic authentication assumes a trusted connection between client and server. Thus, the username and password are transmitted in clear text. More specifically, they are transmitted using Base64 encoding, which is trivially easy to decode. This makes Basic authentication the wrong choice to use over a public network on its own.
Basic Authentication is a long-standing standard supported by nearly all browsers. It also imposes no special requirements on the server side -- users can authenticate against any NT domain, or even against accounts on the local machine. With SSL to shelter the security credentials while they are in transmission, you have an authentication solution that is both highly secure and quite flexible.
Digest Authentication
The Digest authentication option was added in Windows 2000 and IIS 5.0. Like Basic authentication, this is an implementation of a technique suggested by Web standards, namely RFC 2069 (superceded by RFC 2617).
Digest authentication also uses a challenge/response model, but it is much more secure than Basic authentication (when used without SSL). It achieves this greater security not by encrypting the secret (the password) before sending it, but rather by following a different design pattern -- one that does not require the client to transmit the password over the wire at all.
Instead of sending the password itself, the client transmits a one-way message digest (a checksum) of the user's password, using (by default) the MD5 algorithm. The server then fetches the password for that user from a Windows 2000 Domain Controller, reruns the checksum algorithm on it, and compares the two digests. If they match, the server knows that the client knows the correct password, even though the password itself was never sent. (If you have ever wondered what the default ISAPI filter "md5filt" that is installed with IIS 5.0 is used for, now you know.
Integrated Windows Authentication
Integrated Windows authentication (formerly known as NTLM authentication and Windows NT Challenge/Response authentication) can use either NTLM or Kerberos V5 authentication and only works with Internet Explorer 2.0 and later.
When Internet Explorer attempts to access a protected resource, IIS sends two WWW-Authenticate headers, Negotiate and NTLM.
• If Internet Explorer recognizes the Negotiate header, it will choose it because it is listed first. When using Negotiate, the browser will return information for both NTLM and Kerberos. At the server, IIS will use Kerberos if both the client (Internet Explorer 5.0 and later) and server (IIS 5.0 and later) are running Windows 2000 and later, and both are members of the same domain or trusted domains. Otherwise, the server will default to using NTLM.
• If Internet Explorer does not understand Negotiate, it will use NTLM.
So, which mechanism is used depends upon a negotiation between Internet Explorer and IIS.
When used in conjunction with Kerberos v5 authentication, IIS can delegate security credentials among computers running Windows 2000 and later that are trusted and configured for delegation. Delegation enables remote access of resources on behalf of the delegated user.
Integrated Windows authentication is the best authentication scheme in an intranet environment where users have Windows domain accounts, especially when using Kerberos. Integrated Windows authentication, like digest authentication, does not pass the user's password across the network. Instead, a hashed value is exchanged.
Client Certificate Mapping
A certificate is a digitally signed statement that contains information about an entity and the entity's public key, thus binding these two pieces of information together. A trusted organization (or entity) called a Certification Authority (CA) issues a certificate after the CA verifies that the entity is who it says it is. Certificates can contain different types of data. For example, an X.509 certificate includes the format of the certificate, the serial number of the certificate, the algorithm used to sign the certificate, the name of the CA that issued the certificate, the name and public key of the entity requesting the certificate, and the CA's signature. X.509 client certificates simplify authentication for larger user bases because they do not rely on a centralized account database. You can verify a certificate simply by examining the certificate.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vsent7/html/vxconIISAuthentication.asp
4. How to configure the sites in Web server (IIS)?
5. Advantages in IIS 6.0?
http://www.microsoft.com/windowsserver2003/iis/evaluation/features/default.mspx
http://www.microsoft.com/technet/treeview/default.asp?url=/technet/prodtechnol/windowsserver2003/proddocs/datacenter/gs_whatschanged.asp
6. IIS Isolation Levels?
Internet Information Server introduced the notion "Isolation Level", which is also present in IIS4 under a different name. IIS5 supports three isolation levels, that you can set from the Home Directory tab of the site's Properties dialog:
• Low (IIS Process): ASP pages run in INetInfo.Exe, the main IIS process, therefore they are executed in-process. This is the fastest setting, and is the default under IIS4. The problem is that if ASP crashes, IIS crashes as well and must be restarted (IIS5 has a reliable restart feature that automatically restarts a server when a fatal error occurs).
• Medium (Pooled): In this case ASP runs in a different process, which makes this setting more reliable: if ASP crashes IIS won't. All the ASP applications at the Medium isolation level share the same process, so you can have a web site running with just two processes (IIS and ASP process). IIS5 is the first Internet Information Server version that supports this setting, which is also the default setting when you create an IIS5 application. Note that an ASP application that runs at this level is run under COM+, so it's hosted in DLLHOST.EXE (and you can see this executable in the Task Manager).
• High (Isolated): Each ASP application runs out-process in its own process space, therefore if an ASP application crashes, neither IIS nor any other ASP application will be affected. The downside is that you consume more memory and resources if the server hosts many ASP applications. Both IIS4 and IIS5 supports this setting: under IIS4 this process runs inside MTS.EXE, while under IIS5 it runs inside DLLHOST.EXE.
When selecting an isolation level for your ASP application, keep in mind that out-process settings - that is, Medium and High - are less efficient than in-process (Low). However, out-process communication has been vastly improved under IIS5, and in fact IIS5's Medium isolation level often deliver better results than IIS4's Low isolation. In practice, you shouldn't set the Low isolation level for an IIS5 application unless you really need to serve hundreds pages per second.
ASP.net Interview Questions
1. Asp.net and asp – differences?
Code Render Block Code Declaration Block
Compiled
Request/Response Event Driven
Object Oriented - Constructors/Destructors, Inheritance, overloading..
Exception Handling - Try, Catch, Finally
Down-level Support
Cultures
User Controls
In-built client side validation
Session - weren't transferable across servers It can span across servers, It can survive server crashes, can work with browsers that don't support cookies
built on top of the window & IIS, it was always a separate entity & its functionality was limited. its an integral part of OS under the .net framework. It shares many of the same objects that traditional applications would use, and all .net objects are available for asp.net's consumption.
Garbage Collection
Declare variable with datatype
In built graphics support
Cultures
2. How ASP and ASP.NET page works? Explain about asp.net page life cycle?
**
3. Order of events in an asp.net page? Control Execution Lifecycle?
Phase What a control needs to do Method or event to override
Initialize Initialize settings needed during the lifetime of the incoming Web request. Init event (OnInit method)
Load view state At the end of this phase, the ViewState property of a control is automatically populated as described in Maintaining State in a Control. A control can override the default implementation of the LoadViewState method to customize state restoration. LoadViewState method
Process postback data Process incoming form data and update properties accordingly. LoadPostData method (if IPostBackDataHandler is implemented)
Load Perform actions common to all requests, such as setting up a database query. At this point, server controls in the tree are created and initialized, the state is restored, and form controls reflect client-side data. Load event
(OnLoad method)
Send postback change notifications Raise change events in response to state changes between the current and previous postbacks. RaisePostDataChangedEvent method (if IPostBackDataHandler is implemented)
Handle postback events Handle the client-side event that caused the postback and raise appropriate events on the server. RaisePostBackEvent method(if IPostBackEventHandler is implemented)
Prerender Perform any updates before the output is rendered. Any changes made to the state of the control in the prerender phase can be saved, while changes made in the rendering phase are lost. PreRender event
(OnPreRender method)
Save state The ViewState property of a control is automatically persisted to a string object after this stage. This string object is sent to the client and back as a hidden variable. For improving efficiency, a control can override the SaveViewState method to modify the ViewState property. SaveViewState method
Render Generate output to be rendered to the client. Render method
Dispose Perform any final cleanup before the control is torn down. References to expensive resources such as database connections must be released in this phase. Dispose method
Unload Perform any final cleanup before the control is torn down. Control authors generally perform cleanup in Dispose and do not handle this event. UnLoad event (On UnLoad method)
4. Note To override an EventName event, override the OnEventName method (and call base. OnEventName).
5. What are server controls?
ASP.NET server controls are components that run on the server and encapsulate user-interface and other related functionality. They are used in ASP.NET pages and in ASP.NET code-behind classes.
6. What is the difference between Web User Control and Web Custom Control?
Custom Controls
Web custom controls are compiled components that run on the server and that encapsulate user-interface and other related functionality into reusable packages. They can include all the design-time features of standard ASP.NET server controls, including full support for Visual Studio design features such as the Properties window, the visual designer, and the Toolbox.
There are several ways that you can create Web custom controls:
• You can compile a control that combines the functionality of two or more existing controls. For example, if you need a control that encapsulates a button and a text box, you can create it by compiling the existing controls together.
• If an existing server control almost meets your requirements but lacks some required features, you can customize the control by deriving from it and overriding its properties, methods, and events.
• If none of the existing Web server controls (or their combinations) meet your requirements, you can create a custom control by deriving from one of the base control classes. These classes provide all the basic functionality of Web server controls, so you can focus on programming the features you need.
If none of the existing ASP.NET server controls meet the specific requirements of your applications, you can create either a Web user control or a Web custom control that encapsulates the functionality you need. The main difference between the two controls lies in ease of creation vs. ease of use at design time.
Web user controls are easy to make, but they can be less convenient to use in advanced scenarios. You develop Web user controls almost exactly the same way that you develop Web Forms pages. Like Web Forms, user controls can be created in the visual designer, they can be written with code separated from the HTML, and they can handle execution events. However, because Web user controls are compiled dynamically at run time they cannot be added to the Toolbox, and they are represented by a simple placeholder glyph when added to a page. This makes Web user controls harder to use if you are accustomed to full Visual Studio .NET design-time support, including the Properties window and Design view previews. Also, the only way to share the user control between applications is to put a separate copy in each application, which takes more maintenance if you make changes to the control.
Web custom controls are compiled code, which makes them easier to use but more difficult to create; Web custom controls must be authored in code. Once you have created the control, however, you can add it to the Toolbox and display it in a visual designer with full Properties window support and all the other design-time features of ASP.NET server controls. In addition, you can install a single copy of the Web custom control in the global assembly cache and share it between applications, which makes maintenance easier.
Web user controls Web custom controls
Easier to create Harder to create
Limited support for consumers who use a visual design tool Full visual design tool support for consumers
A separate copy of the control is required in each application Only a single copy of the control is required, in the global assembly cache
Cannot be added to the Toolbox in Visual Studio Can be added to the Toolbox in Visual Studio
Good for static layout Good for dynamic layout
(Session/State)
7. Application and Session Events
The ASP.NET page framework provides ways for you to work with events that can be raised when your application starts or stops or when an individual user's session starts or stops:
• Application events are raised for all requests to an application. For example, Application_BeginRequest is raised when any Web Forms page or XML Web service in your application is requested. This event allows you to initialize resources that will be used for each request to the application. A corresponding event, Application_EndRequest, provides you with an opportunity to close or otherwise dispose of resources used for the request.
• Session events are similar to application events (there is a Session_OnStart and a Session_OnEnd event), but are raised with each unique session within the application. A session begins when a user requests a page for the first time from your application and ends either when your application explicitly closes the session or when the session times out.
You can create handlers for these types of events in the Global.asax file.
8. Difference between ASP Session and ASP.NET Session?
asp.net session supports cookie less session & it can span across multiple servers.
9. What is cookie less session? How it works?
By default, ASP.NET will store the session state in the same process that processes the request, just as ASP does. If cookies are not available, a session can be tracked by adding a session identifier to the URL. This can be enabled by setting the following:
http://samples.gotdotnet.com/quickstart/aspplus/doc/stateoverview.aspx
10. How you will handle session when deploying application in more than a server? Describe session handling in a webfarm, how does it work and what are the limits?
By default, ASP.NET will store the session state in the same process that processes the request, just as ASP does. Additionally, ASP.NET can store session data in an external process, which can even reside on another machine. To enable this feature:
• Start the ASP.NET state service, either using the Services snap-in or by executing "net start aspnet_state" on the command line. The state service will by default listen on port 42424. To change the port, modify the registry key for the service: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\aspnet_state\Parameters\Port
• Set the mode attribute of the section to "StateServer".
• Configure the stateConnectionString attribute with the values of the machine on which you started aspnet_state.
The following sample assumes that the state service is running on the same machine as the Web server ("localhost") and uses the default port (42424):
Note that if you try the sample above with this setting, you can reset the Web server (enter iisreset on the command line) and the session state value will persist.
**
11. What method do you use to explicitly kill a users session?
Abandon()
12. What are the different ways you would consider sending data across pages in ASP (i.e between 1.asp to 2.asp)?
Session
public properties
13. What is State Management in .Net and how many ways are there to maintain a state in .Net? What is view state?
Web pages are recreated each time the page is posted to the server. In traditional Web programming, this would ordinarily mean that all information associated with the page and the controls on the page would be lost with each round trip.
To overcome this inherent limitation of traditional Web programming, the ASP.NET page framework includes various options to help you preserve changes — that is, for managing state. The page framework includes a facility called view state that automatically preserves property values of the page and all the controls on it between round trips.
However, you will probably also have application-specific values that you want to preserve. To do so, you can use one of the state management options.
Client-Based State Management Options:
View State
Hidden Form Fields
Cookies
Query Strings
Server-Based State Management Options
Application State
Session State
Database Support
14. What are the disadvantages of view state / what are the benefits?
Automatic view-state management is a feature of server controls that enables them to repopulate their property values on a round trip (without you having to write any code). This feature does impact performance, however, since a server control's view state is passed to and from the server in a hidden form field. You should be aware of when view state helps you and when it hinders your page's performance.
15. When maintaining session through Sql server, what is the impact of Read and Write operation on Session objects? will performance degrade?
Maintaining state using database technology is a common practice when storing user-specific information where the information store is large. Database storage is particularly useful for maintaining long-term state or state that must be preserved even if the server must be restarted.
**
16. What are the contents of cookie?
**
17. How do you create a permanent cookie?
**
18. What is ViewState? What does the "EnableViewState" property do? Why would I want it on or off?
**
19. Explain the differences between Server-side and Client-side code?
Server side code will process at server side & it will send the result to client. Client side code (javascript) will execute only at client side.
20. Can you give an example of what might be best suited to place in the Application_Start and Session_Start subroutines?
**
21. Which ASP.NET configuration options are supported in the ASP.NET implementation on the shared web hosting platform?
A: Many of the ASP.NET configuration options are not configurable at the site, application or subdirectory level on the shared hosting platform. Certain options can affect the security, performance and stability of the server and, therefore cannot be changed. The following settings are the only ones that can be changed in your site’s web.config file (s):
browserCaps
clientTarget
pages
customErrors
globalization
authorization
authentication
webControls
webServices
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconaspnetconfiguration.asp
22. Briefly describe the role of global.asax?
23. How can u debug your .net application?
24. How do u deploy your asp.net application?
25. Where do we store our connection string in asp.net application?
26. Various steps taken to optimize a web based application (caching, stored procedure etc.)
27. How does ASP.NET framework maps client side events to Server side events.
(Security)
28. Security types in ASP/ASP.NET? Different Authentication modes?
29. How .Net has implemented security for web applications?
30. How to do Forms authentication in asp.net?
31. Explain authentication levels in .net ?
32. Explain autherization levels in .net ?
33. What is Role-Based security?
A role is a named set of principals that have the same privileges with respect to security (such as a teller or a manager). A principal can be a member of one or more roles. Therefore, applications can use role membership to determine whether a principal is authorized to perform a requested action.
**
34. How will you do windows authentication and what is the namespace? If a user is logged under integrated windows authentication mode, but he is still not able to logon, what might be the possible cause for this? In ASP.Net application how do you find the name of the logged in person under windows authentication?
35. What are the different authentication modes in the .NET environment?
36.
37.
38. loginUrl="url"
39. protection="All|None|Encryption|Validation"
40. timeout="30" path="/" >
41. requireSSL="true|false"
42. slidingExpiration="true|false">
43.
44.
45.
46.
47.
Attribute Option Description
mode Controls the default authentication mode for an application.
Windows Specifies Windows authentication as the default authentication mode. Use this mode when using any form of Microsoft Internet Information Services (IIS) authentication: Basic, Digest, Integrated Windows authentication (NTLM/Kerberos), or certificates.
Forms Specifies ASP.NET forms-based authentication as the default authentication mode.
Passport Specifies Microsoft Passport authentication as the default authentication mode.
None Specifies no authentication. Only anonymous users are expected or applications can handle events to provide their own authentication.
48. How do you specify whether your data should be passed as Query string and Forms (Mainly about POST and GET)
Through attribute tag of form tag.
49. What is the other method, other than GET and POST, in ASP.NET?
50. What are validator? Name the Validation controls in asp.net? How do u disable them? Will the asp.net validators run in server side or client side? How do you do Client-side validation in .Net? How to disable validator control by client side JavaScript?
A set of server controls included with ASP.NET that test user input in HTML and Web server controls for programmer-defined requirements. Validation controls perform input checking in server code. If the user is working with a browser that supports DHTML, the validation controls can also perform validation ("EnableClientScript" property set to true/false) using client script.
The following validation controls are available in asp.net:
RequiredFieldValidator Control, CompareValidator Control, RangeValidator Control, RegularExpressionValidator Control, CustomValidator Control, ValidationSummary Control.
51. Which two properties are there on every validation control?
ControlToValidate, ErrorMessage
52. How do you use css in asp.net?
Within the section of an HTML document that will use these styles, add a link to this external CSS style sheet that
follows this form:
MyStyles.css is the name of your external CSS style sheet.
53. How do you implement postback with a text box? What is postback and usestate?
Make AutoPostBack property to true
54. How can you debug an ASP page, without touching the code?
55. What is SQL injection?
An SQL injection attack "injects" or manipulates SQL code by adding unexpected SQL to a query.
Many web pages take parameters from web user, and make SQL query to the database. Take for instance when a user login, web page that user name and password and make SQL query to the database to check if a user has valid name and password.
Username: ' or 1=1 ---
Password: [Empty]
This would execute the following query against the users table:
select count(*) from users where userName='' or 1=1 --' and userPass=''
56. How can u handle Exceptions in Asp.Net?
57. How can u handle Un Managed Code Exceptions in ASP.Net?
58. Asp.net - How to find last error which occurred?
A: Server.GetLastError();
[C#]
Exception LastError;
String ErrMessage;
LastError = Server.GetLastError();
if (LastError != null)
ErrMessage = LastError.Message;
else
ErrMessage = "No Errors";
Response.Write("Last Error = " + ErrMessage);
59. How to do Caching in ASP?
A: <%@ OutputCache Duration="60" VaryByParam="None" %>
VaryByParam value Description
none One version of page cached (only raw GET)
* n versions of page cached based on query string and/or POST body
v1 n versions of page cached based on value of v1 variable in query string or POST body
v1;v2 n versions of page cached based on value of v1 and v2 variables in query string or POST body
60. <%@ OutputCache Duration="60" VaryByParam="none" %>
<%@ OutputCache Duration="60" VaryByParam="*" %>
<%@ OutputCache Duration="60" VaryByParam="name;age" %>
The OutputCache directive supports several other cache varying options
• VaryByHeader - maintain separate cache entry for header string changes (UserAgent, UserLanguage, etc.)
• VaryByControl - for user controls, maintain separate cache entry for properties of a user control
• VaryByCustom - can specify separate cache entries for browser types and version or provide a custom GetVaryByCustomString method in HttpApplicationderived class
61. What is the Global ASA(X) File?
62. Any alternative to avoid name collisions other then Namespaces.
A scenario that two namespaces named N1 and N2 are there both having the same class say A. now in another class i ve written
using N1;using N2;
and i am instantiating class A in this class. Then how will u avoid name collisions?
Ans: using alias
Eg: using MyAlias = MyCompany.Proj.Nested;
63. Which is the namespace used to write error message in event Log File?
64. What are the page level transaction and class level transaction?
65. What are different transaction options?
66. What is the namespace for encryption?
67. What is the difference between application and cache variables?
68. What is the difference between control and component?
69. You ve defined one page_load event in aspx page and same page_load event in code behind how will prog run?
70. Where would you use an IHttpModule, and what are the limitations of any approach you might take in implementing one?
71. Can you edit data in the Repeater control? Which template must you provide, in order to display data in a Repeater control? How can you provide an alternating color scheme in a Repeater control? What property must you set, and what method must you call in your code, in order to bind the data from some data source to the Repeater control?
72. What is the use of web.config? Difference between machine.config and Web.config?
ASP.NET configuration files are XML-based text files--each named web.config--that can appear in any directory on an ASP.NET
Web application server. Each web.config file applies configuration settings to the directory it is located in and to all
virtual child directories beneath it. Settings in child directories can optionally override or modify settings specified in
parent directories. The root configuration file--WinNT\Microsoft.NET\Framework\\config\machine.config--provides
default configuration settings for the entire machine. ASP.NET configures IIS to prevent direct browser access to web.config
files to ensure that their values cannot become public (attempts to access them will cause ASP.NET to return 403: Access
Forbidden).
At run time ASP.NET uses these web.config configuration files to hierarchically compute a unique collection of settings for
each incoming URL target request (these settings are calculated only once and then cached across subsequent requests; ASP.NET
automatically watches for file changes and will invalidate the cache if any of the configuration files change).
http://samples.gotdotnet.com/quickstart/aspplus/doc/configformat.aspx
73. What is the use of sessionstate tag in the web.config file?
Configuring session state: Session state features can be configured via the section in a web.config file. To double the default timeout of 20 minutes, you can add the following to the web.config file of an application:
timeout="40"
/>
74. What are the different modes for the sessionstates in the web.config file?
Off Indicates that session state is not enabled.
Inproc Indicates that session state is stored locally.
StateServer Indicates that session state is stored on a remote server.
SQLServer Indicates that session state is stored on the SQL Server.
75. What is smart navigation?
When a page is requested by an Internet Explorer 5 browser, or later, smart navigation enhances the user's experience of the page by performing the following:
• eliminating the flash caused by navigation.
• persisting the scroll position when moving from page to page.
• persisting element focus between navigations.
• retaining only the last page state in the browser's history.
Smart navigation is best used with ASP.NET pages that require frequent postbacks but with visual content that does not change dramatically on return. Consider this carefully when deciding whether to set this property to true.
Set the SmartNavigation attribute to true in the @ Page directive in the .aspx file. When the page is requested, the dynamically generated class sets this property.
76. In what order do the events of an ASPX page execute. As a developer is it important to undertsand these events?
77. How would you get ASP.NET running in Apache web servers - why would you even do this?
78. What tags do you need to add within the asp:datagrid tags to bind columns manually
79. What base class do all Web Forms inherit from?
System.Web.UI.Page
80. How can we create pie chart in asp.net?
81. Is it possible for me to change my aspx file extension to some other name?
Yes.
Open IIS->Default Website -> Properties
Select HomeDirectory tab
Click on configuration button
Click on add. Enter aspnet_isapi details (C:\WINDOWS\Microsoft.NET\Framework\v1.0.3705\aspnet_isapi.dll | GET,HEAD,POST,DEBUG)
Open machine.config(C:\WINDOWS\Microsoft.NET\Framework\v1.0.3705\CONFIG) & add new extension under tag
What is AutoEventWireup attribute for ?
Code Render Block Code Declaration Block
Compiled
Request/Response Event Driven
Object Oriented - Constructors/Destructors, Inheritance, overloading..
Exception Handling - Try, Catch, Finally
Down-level Support
Cultures
User Controls
In-built client side validation
Session - weren't transferable across servers It can span across servers, It can survive server crashes, can work with browsers that don't support cookies
built on top of the window & IIS, it was always a separate entity & its functionality was limited. its an integral part of OS under the .net framework. It shares many of the same objects that traditional applications would use, and all .net objects are available for asp.net's consumption.
Garbage Collection
Declare variable with datatype
In built graphics support
Cultures
2. How ASP and ASP.NET page works? Explain about asp.net page life cycle?
**
3. Order of events in an asp.net page? Control Execution Lifecycle?
Phase What a control needs to do Method or event to override
Initialize Initialize settings needed during the lifetime of the incoming Web request. Init event (OnInit method)
Load view state At the end of this phase, the ViewState property of a control is automatically populated as described in Maintaining State in a Control. A control can override the default implementation of the LoadViewState method to customize state restoration. LoadViewState method
Process postback data Process incoming form data and update properties accordingly. LoadPostData method (if IPostBackDataHandler is implemented)
Load Perform actions common to all requests, such as setting up a database query. At this point, server controls in the tree are created and initialized, the state is restored, and form controls reflect client-side data. Load event
(OnLoad method)
Send postback change notifications Raise change events in response to state changes between the current and previous postbacks. RaisePostDataChangedEvent method (if IPostBackDataHandler is implemented)
Handle postback events Handle the client-side event that caused the postback and raise appropriate events on the server. RaisePostBackEvent method(if IPostBackEventHandler is implemented)
Prerender Perform any updates before the output is rendered. Any changes made to the state of the control in the prerender phase can be saved, while changes made in the rendering phase are lost. PreRender event
(OnPreRender method)
Save state The ViewState property of a control is automatically persisted to a string object after this stage. This string object is sent to the client and back as a hidden variable. For improving efficiency, a control can override the SaveViewState method to modify the ViewState property. SaveViewState method
Render Generate output to be rendered to the client. Render method
Dispose Perform any final cleanup before the control is torn down. References to expensive resources such as database connections must be released in this phase. Dispose method
Unload Perform any final cleanup before the control is torn down. Control authors generally perform cleanup in Dispose and do not handle this event. UnLoad event (On UnLoad method)
4. Note To override an EventName event, override the OnEventName method (and call base. OnEventName).
5. What are server controls?
ASP.NET server controls are components that run on the server and encapsulate user-interface and other related functionality. They are used in ASP.NET pages and in ASP.NET code-behind classes.
6. What is the difference between Web User Control and Web Custom Control?
Custom Controls
Web custom controls are compiled components that run on the server and that encapsulate user-interface and other related functionality into reusable packages. They can include all the design-time features of standard ASP.NET server controls, including full support for Visual Studio design features such as the Properties window, the visual designer, and the Toolbox.
There are several ways that you can create Web custom controls:
• You can compile a control that combines the functionality of two or more existing controls. For example, if you need a control that encapsulates a button and a text box, you can create it by compiling the existing controls together.
• If an existing server control almost meets your requirements but lacks some required features, you can customize the control by deriving from it and overriding its properties, methods, and events.
• If none of the existing Web server controls (or their combinations) meet your requirements, you can create a custom control by deriving from one of the base control classes. These classes provide all the basic functionality of Web server controls, so you can focus on programming the features you need.
If none of the existing ASP.NET server controls meet the specific requirements of your applications, you can create either a Web user control or a Web custom control that encapsulates the functionality you need. The main difference between the two controls lies in ease of creation vs. ease of use at design time.
Web user controls are easy to make, but they can be less convenient to use in advanced scenarios. You develop Web user controls almost exactly the same way that you develop Web Forms pages. Like Web Forms, user controls can be created in the visual designer, they can be written with code separated from the HTML, and they can handle execution events. However, because Web user controls are compiled dynamically at run time they cannot be added to the Toolbox, and they are represented by a simple placeholder glyph when added to a page. This makes Web user controls harder to use if you are accustomed to full Visual Studio .NET design-time support, including the Properties window and Design view previews. Also, the only way to share the user control between applications is to put a separate copy in each application, which takes more maintenance if you make changes to the control.
Web custom controls are compiled code, which makes them easier to use but more difficult to create; Web custom controls must be authored in code. Once you have created the control, however, you can add it to the Toolbox and display it in a visual designer with full Properties window support and all the other design-time features of ASP.NET server controls. In addition, you can install a single copy of the Web custom control in the global assembly cache and share it between applications, which makes maintenance easier.
Web user controls Web custom controls
Easier to create Harder to create
Limited support for consumers who use a visual design tool Full visual design tool support for consumers
A separate copy of the control is required in each application Only a single copy of the control is required, in the global assembly cache
Cannot be added to the Toolbox in Visual Studio Can be added to the Toolbox in Visual Studio
Good for static layout Good for dynamic layout
(Session/State)
7. Application and Session Events
The ASP.NET page framework provides ways for you to work with events that can be raised when your application starts or stops or when an individual user's session starts or stops:
• Application events are raised for all requests to an application. For example, Application_BeginRequest is raised when any Web Forms page or XML Web service in your application is requested. This event allows you to initialize resources that will be used for each request to the application. A corresponding event, Application_EndRequest, provides you with an opportunity to close or otherwise dispose of resources used for the request.
• Session events are similar to application events (there is a Session_OnStart and a Session_OnEnd event), but are raised with each unique session within the application. A session begins when a user requests a page for the first time from your application and ends either when your application explicitly closes the session or when the session times out.
You can create handlers for these types of events in the Global.asax file.
8. Difference between ASP Session and ASP.NET Session?
asp.net session supports cookie less session & it can span across multiple servers.
9. What is cookie less session? How it works?
By default, ASP.NET will store the session state in the same process that processes the request, just as ASP does. If cookies are not available, a session can be tracked by adding a session identifier to the URL. This can be enabled by setting the following:
http://samples.gotdotnet.com/quickstart/aspplus/doc/stateoverview.aspx
10. How you will handle session when deploying application in more than a server? Describe session handling in a webfarm, how does it work and what are the limits?
By default, ASP.NET will store the session state in the same process that processes the request, just as ASP does. Additionally, ASP.NET can store session data in an external process, which can even reside on another machine. To enable this feature:
• Start the ASP.NET state service, either using the Services snap-in or by executing "net start aspnet_state" on the command line. The state service will by default listen on port 42424. To change the port, modify the registry key for the service: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\aspnet_state\Parameters\Port
• Set the mode attribute of the
• Configure the stateConnectionString attribute with the values of the machine on which you started aspnet_state.
The following sample assumes that the state service is running on the same machine as the Web server ("localhost") and uses the default port (42424):
Note that if you try the sample above with this setting, you can reset the Web server (enter iisreset on the command line) and the session state value will persist.
**
11. What method do you use to explicitly kill a users session?
Abandon()
12. What are the different ways you would consider sending data across pages in ASP (i.e between 1.asp to 2.asp)?
Session
public properties
13. What is State Management in .Net and how many ways are there to maintain a state in .Net? What is view state?
Web pages are recreated each time the page is posted to the server. In traditional Web programming, this would ordinarily mean that all information associated with the page and the controls on the page would be lost with each round trip.
To overcome this inherent limitation of traditional Web programming, the ASP.NET page framework includes various options to help you preserve changes — that is, for managing state. The page framework includes a facility called view state that automatically preserves property values of the page and all the controls on it between round trips.
However, you will probably also have application-specific values that you want to preserve. To do so, you can use one of the state management options.
Client-Based State Management Options:
View State
Hidden Form Fields
Cookies
Query Strings
Server-Based State Management Options
Application State
Session State
Database Support
14. What are the disadvantages of view state / what are the benefits?
Automatic view-state management is a feature of server controls that enables them to repopulate their property values on a round trip (without you having to write any code). This feature does impact performance, however, since a server control's view state is passed to and from the server in a hidden form field. You should be aware of when view state helps you and when it hinders your page's performance.
15. When maintaining session through Sql server, what is the impact of Read and Write operation on Session objects? will performance degrade?
Maintaining state using database technology is a common practice when storing user-specific information where the information store is large. Database storage is particularly useful for maintaining long-term state or state that must be preserved even if the server must be restarted.
**
16. What are the contents of cookie?
**
17. How do you create a permanent cookie?
**
18. What is ViewState? What does the "EnableViewState" property do? Why would I want it on or off?
**
19. Explain the differences between Server-side and Client-side code?
Server side code will process at server side & it will send the result to client. Client side code (javascript) will execute only at client side.
20. Can you give an example of what might be best suited to place in the Application_Start and Session_Start subroutines?
**
21. Which ASP.NET configuration options are supported in the ASP.NET implementation on the shared web hosting platform?
A: Many of the ASP.NET configuration options are not configurable at the site, application or subdirectory level on the shared hosting platform. Certain options can affect the security, performance and stability of the server and, therefore cannot be changed. The following settings are the only ones that can be changed in your site’s web.config file (s):
browserCaps
clientTarget
pages
customErrors
globalization
authorization
authentication
webControls
webServices
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconaspnetconfiguration.asp
22. Briefly describe the role of global.asax?
23. How can u debug your .net application?
24. How do u deploy your asp.net application?
25. Where do we store our connection string in asp.net application?
26. Various steps taken to optimize a web based application (caching, stored procedure etc.)
27. How does ASP.NET framework maps client side events to Server side events.
(Security)
28. Security types in ASP/ASP.NET? Different Authentication modes?
29. How .Net has implemented security for web applications?
30. How to do Forms authentication in asp.net?
31. Explain authentication levels in .net ?
32. Explain autherization levels in .net ?
33. What is Role-Based security?
A role is a named set of principals that have the same privileges with respect to security (such as a teller or a manager). A principal can be a member of one or more roles. Therefore, applications can use role membership to determine whether a principal is authorized to perform a requested action.
**
34. How will you do windows authentication and what is the namespace? If a user is logged under integrated windows authentication mode, but he is still not able to logon, what might be the possible cause for this? In ASP.Net application how do you find the name of the logged in person under windows authentication?
35. What are the different authentication modes in the .NET environment?
36.
37.
38. loginUrl="url"
39. protection="All|None|Encryption|Validation"
40. timeout="30" path="/" >
41. requireSSL="true|false"
42. slidingExpiration="true|false">
43.
44.
45.
46.
47.
Attribute Option Description
mode Controls the default authentication mode for an application.
Windows Specifies Windows authentication as the default authentication mode. Use this mode when using any form of Microsoft Internet Information Services (IIS) authentication: Basic, Digest, Integrated Windows authentication (NTLM/Kerberos), or certificates.
Forms Specifies ASP.NET forms-based authentication as the default authentication mode.
Passport Specifies Microsoft Passport authentication as the default authentication mode.
None Specifies no authentication. Only anonymous users are expected or applications can handle events to provide their own authentication.
48. How do you specify whether your data should be passed as Query string and Forms (Mainly about POST and GET)
Through attribute tag of form tag.
49. What is the other method, other than GET and POST, in ASP.NET?
50. What are validator? Name the Validation controls in asp.net? How do u disable them? Will the asp.net validators run in server side or client side? How do you do Client-side validation in .Net? How to disable validator control by client side JavaScript?
A set of server controls included with ASP.NET that test user input in HTML and Web server controls for programmer-defined requirements. Validation controls perform input checking in server code. If the user is working with a browser that supports DHTML, the validation controls can also perform validation ("EnableClientScript" property set to true/false) using client script.
The following validation controls are available in asp.net:
RequiredFieldValidator Control, CompareValidator Control, RangeValidator Control, RegularExpressionValidator Control, CustomValidator Control, ValidationSummary Control.
51. Which two properties are there on every validation control?
ControlToValidate, ErrorMessage
52. How do you use css in asp.net?
Within the section of an HTML document that will use these styles, add a link to this external CSS style sheet that
follows this form:
MyStyles.css is the name of your external CSS style sheet.
53. How do you implement postback with a text box? What is postback and usestate?
Make AutoPostBack property to true
54. How can you debug an ASP page, without touching the code?
55. What is SQL injection?
An SQL injection attack "injects" or manipulates SQL code by adding unexpected SQL to a query.
Many web pages take parameters from web user, and make SQL query to the database. Take for instance when a user login, web page that user name and password and make SQL query to the database to check if a user has valid name and password.
Username: ' or 1=1 ---
Password: [Empty]
This would execute the following query against the users table:
select count(*) from users where userName='' or 1=1 --' and userPass=''
56. How can u handle Exceptions in Asp.Net?
57. How can u handle Un Managed Code Exceptions in ASP.Net?
58. Asp.net - How to find last error which occurred?
A: Server.GetLastError();
[C#]
Exception LastError;
String ErrMessage;
LastError = Server.GetLastError();
if (LastError != null)
ErrMessage = LastError.Message;
else
ErrMessage = "No Errors";
Response.Write("Last Error = " + ErrMessage);
59. How to do Caching in ASP?
A: <%@ OutputCache Duration="60" VaryByParam="None" %>
VaryByParam value Description
none One version of page cached (only raw GET)
* n versions of page cached based on query string and/or POST body
v1 n versions of page cached based on value of v1 variable in query string or POST body
v1;v2 n versions of page cached based on value of v1 and v2 variables in query string or POST body
60. <%@ OutputCache Duration="60" VaryByParam="none" %>
<%@ OutputCache Duration="60" VaryByParam="*" %>
<%@ OutputCache Duration="60" VaryByParam="name;age" %>
The OutputCache directive supports several other cache varying options
• VaryByHeader - maintain separate cache entry for header string changes (UserAgent, UserLanguage, etc.)
• VaryByControl - for user controls, maintain separate cache entry for properties of a user control
• VaryByCustom - can specify separate cache entries for browser types and version or provide a custom GetVaryByCustomString method in HttpApplicationderived class
61. What is the Global ASA(X) File?
62. Any alternative to avoid name collisions other then Namespaces.
A scenario that two namespaces named N1 and N2 are there both having the same class say A. now in another class i ve written
using N1;using N2;
and i am instantiating class A in this class. Then how will u avoid name collisions?
Ans: using alias
Eg: using MyAlias = MyCompany.Proj.Nested;
63. Which is the namespace used to write error message in event Log File?
64. What are the page level transaction and class level transaction?
65. What are different transaction options?
66. What is the namespace for encryption?
67. What is the difference between application and cache variables?
68. What is the difference between control and component?
69. You ve defined one page_load event in aspx page and same page_load event in code behind how will prog run?
70. Where would you use an IHttpModule, and what are the limitations of any approach you might take in implementing one?
71. Can you edit data in the Repeater control? Which template must you provide, in order to display data in a Repeater control? How can you provide an alternating color scheme in a Repeater control? What property must you set, and what method must you call in your code, in order to bind the data from some data source to the Repeater control?
72. What is the use of web.config? Difference between machine.config and Web.config?
ASP.NET configuration files are XML-based text files--each named web.config--that can appear in any directory on an ASP.NET
Web application server. Each web.config file applies configuration settings to the directory it is located in and to all
virtual child directories beneath it. Settings in child directories can optionally override or modify settings specified in
parent directories. The root configuration file--WinNT\Microsoft.NET\Framework\
default configuration settings for the entire machine. ASP.NET configures IIS to prevent direct browser access to web.config
files to ensure that their values cannot become public (attempts to access them will cause ASP.NET to return 403: Access
Forbidden).
At run time ASP.NET uses these web.config configuration files to hierarchically compute a unique collection of settings for
each incoming URL target request (these settings are calculated only once and then cached across subsequent requests; ASP.NET
automatically watches for file changes and will invalidate the cache if any of the configuration files change).
http://samples.gotdotnet.com/quickstart/aspplus/doc/configformat.aspx
73. What is the use of sessionstate tag in the web.config file?
Configuring session state: Session state features can be configured via the
timeout="40"
/>
74. What are the different modes for the sessionstates in the web.config file?
Off Indicates that session state is not enabled.
Inproc Indicates that session state is stored locally.
StateServer Indicates that session state is stored on a remote server.
SQLServer Indicates that session state is stored on the SQL Server.
75. What is smart navigation?
When a page is requested by an Internet Explorer 5 browser, or later, smart navigation enhances the user's experience of the page by performing the following:
• eliminating the flash caused by navigation.
• persisting the scroll position when moving from page to page.
• persisting element focus between navigations.
• retaining only the last page state in the browser's history.
Smart navigation is best used with ASP.NET pages that require frequent postbacks but with visual content that does not change dramatically on return. Consider this carefully when deciding whether to set this property to true.
Set the SmartNavigation attribute to true in the @ Page directive in the .aspx file. When the page is requested, the dynamically generated class sets this property.
76. In what order do the events of an ASPX page execute. As a developer is it important to undertsand these events?
77. How would you get ASP.NET running in Apache web servers - why would you even do this?
78. What tags do you need to add within the asp:datagrid tags to bind columns manually
79. What base class do all Web Forms inherit from?
System.Web.UI.Page
80. How can we create pie chart in asp.net?
81. Is it possible for me to change my aspx file extension to some other name?
Yes.
Open IIS->Default Website -> Properties
Select HomeDirectory tab
Click on configuration button
Click on add. Enter aspnet_isapi details (C:\WINDOWS\Microsoft.NET\Framework\v1.0.3705\aspnet_isapi.dll | GET,HEAD,POST,DEBUG)
Open machine.config(C:\WINDOWS\Microsoft.NET\Framework\v1.0.3705\CONFIG) & add new extension under
What is AutoEventWireup attribute for ?
.net Constructors Interview Questions
CONSTRUCTORS
1. Difference between type constructor and instance constructor? What is static constructor, when it will be fired? And what is its use?
(Class constructor method is also known as type constructor or type initializer)
Instance constructor is executed when a new instance of type is created and the class constructor is executed after the type is loaded and before any one of the type members is accessed. (It will get executed only 1st time, when we call any static methods/fields in the same class.) Class constructors are used for static field initialization. Only one class constructor per type is permitted, and it cannot use the vararg (variable argument) calling convention.
A static constructor is used to initialize a class. It is called automatically to initialize the class before the first instance is created or any static members are referenced.
2. What is Private Constructor? and it’s use? Can you create instance of a class which has Private Constructor?
A: When a class declares only private instance constructors, it is not possible for classes outside the program to derive from the class or to directly create instances of it. (Except Nested classes)
Make a constructor private if:
- You want it to be available only to the class itself. For example, you might have a special constructor used only in the implementation of your class' Clone method.
- You do not want instances of your component to be created. For example, you may have a class containing nothing but Shared utility functions, and no instance data. Creating instances of the class would waste memory.
3. I have 3 overloaded constructors in my class. In order to avoid making instance of the class do I need to make all constructors to private?
(yes)
4. Overloaded constructor will call default constructor internally?
(no)
5. What are virtual destructors?
6. Destructor and finalize
Generally in C++ the destructor is called when objects gets destroyed. And one can explicitly call the destructors in C++. And also the objects are destroyed in reverse order that they are created in. So in C++ you have control over the destructors.
In C# you can never call them, the reason is one cannot destroy an object. So who has the control over the destructor (in C#)? it's the .Net frameworks Garbage Collector (GC). GC destroys the objects only when necessary. Some situations of necessity are memory is exhausted or user explicitly calls System.GC.Collect() method.
Points to remember:
1. Destructors are invoked automatically, and cannot be invoked explicitly.
2. Destructors cannot be overloaded. Thus, a class can have, at most, one destructor.
3. Destructors are not inherited. Thus, a class has no destructors other than the one, which may be declared in it.
4. Destructors cannot be used with structs. They are only used with classes.
5. An instance becomes eligible for destruction when it is no longer possible for any code to use the instance.
6. Execution of the destructor for the instance may occur at any time after the instance becomes eligible for destruction.
7. When an instance is destructed, the destructors in its inheritance chain are called, in order, from most derived to least derived.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconfinalizemethodscdestructors.asp
7. What is the difference between Finalize and Dispose (Garbage collection)
Class instances often encapsulate control over resources that are not managed by the runtime, such as window handles (HWND), database connections, and so on. Therefore, you should provide both an explicit and an implicit way to free those resources. Provide implicit control by implementing the protected Finalize Method on an object (destructor syntax in C# and the Managed Extensions for C++). The garbage collector calls this method at some point after there are no longer any valid references to the object.
In some cases, you might want to provide programmers using an object with the ability to explicitly release these external resources before the garbage collector frees the object. If an external resource is scarce or expensive, better performance can be achieved if the programmer explicitly releases resources when they are no longer being used. To provide explicit control, implement the Dispose method provided by the IDisposable Interface. The consumer of the object should call this method when it is done using the object. Dispose can be called even if other references to the object are alive.
Note that even when you provide explicit control by way of Dispose, you should provide implicit cleanup using the Finalize method. Finalize provides a backup to prevent resources from permanently leaking if the programmer fails to call Dispose.
8. What is close method? How its different from Finalize & Dispose?
**
9. What is boxing & unboxing?
10. What is check/uncheck?
11. What is the use of base keyword? Tell me a practical example for base keyword’s usage?
12. What are the different .net tools which u used in projects?
13. What will do to avoid prior case?
14. Will it go to finally block if there is no exception happened?
Ans: Yes. The finally block is useful for cleaning up any resources allocated in the try block. Control is always passed to the finally block regardless of how the try block exits.
15. Is goto statement supported in C#? How about Java?
Gotos are supported in C#to the fullest. In Java goto is a reserved keyword that provides absolutely no functionality.
16. What’s different about switch statements in C#?
No fall-throughs allowed. Unlike the C++ switch statement, C# does not support an explicit fall through from one case label to another. If you want, you can use goto a switch-case, or goto default.
case 1:
cost += 25;
break;
case 2:
cost += 25;
goto case 1;
1. Difference between type constructor and instance constructor? What is static constructor, when it will be fired? And what is its use?
(Class constructor method is also known as type constructor or type initializer)
Instance constructor is executed when a new instance of type is created and the class constructor is executed after the type is loaded and before any one of the type members is accessed. (It will get executed only 1st time, when we call any static methods/fields in the same class.) Class constructors are used for static field initialization. Only one class constructor per type is permitted, and it cannot use the vararg (variable argument) calling convention.
A static constructor is used to initialize a class. It is called automatically to initialize the class before the first instance is created or any static members are referenced.
2. What is Private Constructor? and it’s use? Can you create instance of a class which has Private Constructor?
A: When a class declares only private instance constructors, it is not possible for classes outside the program to derive from the class or to directly create instances of it. (Except Nested classes)
Make a constructor private if:
- You want it to be available only to the class itself. For example, you might have a special constructor used only in the implementation of your class' Clone method.
- You do not want instances of your component to be created. For example, you may have a class containing nothing but Shared utility functions, and no instance data. Creating instances of the class would waste memory.
3. I have 3 overloaded constructors in my class. In order to avoid making instance of the class do I need to make all constructors to private?
(yes)
4. Overloaded constructor will call default constructor internally?
(no)
5. What are virtual destructors?
6. Destructor and finalize
Generally in C++ the destructor is called when objects gets destroyed. And one can explicitly call the destructors in C++. And also the objects are destroyed in reverse order that they are created in. So in C++ you have control over the destructors.
In C# you can never call them, the reason is one cannot destroy an object. So who has the control over the destructor (in C#)? it's the .Net frameworks Garbage Collector (GC). GC destroys the objects only when necessary. Some situations of necessity are memory is exhausted or user explicitly calls System.GC.Collect() method.
Points to remember:
1. Destructors are invoked automatically, and cannot be invoked explicitly.
2. Destructors cannot be overloaded. Thus, a class can have, at most, one destructor.
3. Destructors are not inherited. Thus, a class has no destructors other than the one, which may be declared in it.
4. Destructors cannot be used with structs. They are only used with classes.
5. An instance becomes eligible for destruction when it is no longer possible for any code to use the instance.
6. Execution of the destructor for the instance may occur at any time after the instance becomes eligible for destruction.
7. When an instance is destructed, the destructors in its inheritance chain are called, in order, from most derived to least derived.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconfinalizemethodscdestructors.asp
7. What is the difference between Finalize and Dispose (Garbage collection)
Class instances often encapsulate control over resources that are not managed by the runtime, such as window handles (HWND), database connections, and so on. Therefore, you should provide both an explicit and an implicit way to free those resources. Provide implicit control by implementing the protected Finalize Method on an object (destructor syntax in C# and the Managed Extensions for C++). The garbage collector calls this method at some point after there are no longer any valid references to the object.
In some cases, you might want to provide programmers using an object with the ability to explicitly release these external resources before the garbage collector frees the object. If an external resource is scarce or expensive, better performance can be achieved if the programmer explicitly releases resources when they are no longer being used. To provide explicit control, implement the Dispose method provided by the IDisposable Interface. The consumer of the object should call this method when it is done using the object. Dispose can be called even if other references to the object are alive.
Note that even when you provide explicit control by way of Dispose, you should provide implicit cleanup using the Finalize method. Finalize provides a backup to prevent resources from permanently leaking if the programmer fails to call Dispose.
8. What is close method? How its different from Finalize & Dispose?
**
9. What is boxing & unboxing?
10. What is check/uncheck?
11. What is the use of base keyword? Tell me a practical example for base keyword’s usage?
12. What are the different .net tools which u used in projects?
13. What will do to avoid prior case?
14. Will it go to finally block if there is no exception happened?
Ans: Yes. The finally block is useful for cleaning up any resources allocated in the try block. Control is always passed to the finally block regardless of how the try block exits.
15. Is goto statement supported in C#? How about Java?
Gotos are supported in C#to the fullest. In Java goto is a reserved keyword that provides absolutely no functionality.
16. What’s different about switch statements in C#?
No fall-throughs allowed. Unlike the C++ switch statement, C# does not support an explicit fall through from one case label to another. If you want, you can use goto a switch-case, or goto default.
case 1:
cost += 25;
break;
case 2:
cost += 25;
goto case 1;
.net Framework OOPS
1. What are the OOPS concepts?
1) Encapsulation: It is the mechanism that binds together code and data in manipulates, and keeps both safe from outside interference and misuse. In short it isolates a particular code and data from all other codes and data. A well-defined interface controls the access to that particular code and data.
2) Inheritance: It is the process by which one object acquires the properties of another object. This supports the hierarchical classification. Without the use of hierarchies, each object would need to define all its characteristics explicitly. However, by use of inheritance, an object need only define those qualities that make it unique within its class. It can inherit its general attributes from its parent. A new sub-class inherits all of the attributes of all of its ancestors.
3) Polymorphism: It is a feature that allows one interface to be used for general class of actions. The specific action is determined by the exact nature of the situation. In general polymorphism means "one interface, multiple methods", This means that it is possible to design a generic interface to a group of related activities. This helps reduce complexity by allowing the same interface to be used to specify a general class of action. It is the compiler's job to select the specific action (that is, method) as it applies to each situation.
2. What is the difference between a Struct and a Class?
o The struct type is suitable for representing lightweight objects such as Point, Rectangle, and Color. Although it is possible to represent a point as a class, a struct is more efficient in some scenarios. For example, if you declare an array of 1000 Point objects, you will allocate additional memory for referencing each object. In this case, the struct is less expensive.
o When you create a struct object using the new operator, it gets created and the appropriate constructor is called. Unlike classes, structs can be instantiated without using the new operator. If you do not use new, the fields will remain unassigned and the object cannot be used until all of the fields are initialized.
o It is an error to declare a default (parameterless) constructor for a struct. A default constructor is always provided to initialize the struct members to their default values.
o It is an error to initialize an instance field in a struct.
o There is no inheritance for structs as there is for classes. A struct cannot inherit from another struct or class, and it cannot be the base of a class. Structs, however, inherit from the base class Object. A struct can implement interfaces, and it does that exactly as classes do.
o A struct is a value type, while a class is a reference type.
3. Value type & reference types difference? Example from .NET. Integer & struct are value types or reference types in .NET?
Most programming languages provide built-in data types, such as integers and floating-point numbers, that are copied when they are passed as arguments (that is, they are passed by value). In the .NET Framework, these are called value types. The runtime supports two kinds of value types:
• Built-in value types
The .NET Framework defines built-in value types, such as System.Int32 and System.Boolean, which correspond and are identical to primitive data types used by programming languages.
• User-defined value types
Your language will provide ways to define your own value types, which derive from System.ValueType. If you want to define a type representing a value that is small, such as a complex number (using two floating-point numbers), you might choose to define it as a value type because you can pass the value type efficiently by value. If the type you are defining would be more efficiently passed by reference, you should define it as a class instead.
Variables of reference types, referred to as objects, store references to the actual data. This following are the reference types:
• class
• interface
• delegate
This following are the built-in reference types:
• object
• string
4. What is Inheritance, Multiple Inheritance, Shared and Repeatable Inheritance?
**
5. What is Method overloading?
Method overloading occurs when a class contains two methods with the same name, but different signatures.
6. What is Method Overriding? How to override a function in C#?
Use the override modifier to modify a method, a property, an indexer, or an event. An override method provides a new implementation of a member inherited from a base class. The method overridden by an override declaration is known as the overridden base method. The overridden base method must have the same signature as the override method.
You cannot override a non-virtual or static method. The overridden base method must be virtual, abstract, or override.
7. Can we call a base class method without creating instance?
Its possible If its a static method.
Its possible by inheriting from that class also.
Its possible from derived classes using base keyword.
8. You have one base class virtual function how will call that function from derived class?
Ans:
9. class a
10. {
11. public virtual int m()
12. {
13. return 1;
14. }
15. }
16. class b:a
17. {
18. public int j()
19. {
20. return m();
21. }
}
22. In which cases you use override and new base?
Use the new modifier to explicitly hide a member inherited from a base class. To hide an inherited member, declare it in the derived class using the same name, and modify it with the new modifier.
C# Language features
23. What are Sealed Classes in C#?
The sealed modifier is used to prevent derivation from a class. A compile-time error occurs if a sealed class is specified as the base class of another class. (A sealed class cannot also be an abstract class)
24. What is Polymorphism? How does VB.NET/C# achieve polymorphism?
**
25. class Token
26. {
27. public string Display()
28. {
29. //Implementation goes here
30. return "base";
31. }
32. }
33. class IdentifierToken:Token
34. {
35. public new string Display() //What is the use of new keyword
36. {
37. //Implementation goes here
38. return "derive";
39. }
40. }
41. static void Method(Token t)
42. {
43. Console.Write(t.Display());
44. }
45. public static void Main()
46. {
47. IdentifierToken Variable=new IdentifierToken();
48. Method(Variable); //Which Class Method is called here
49. Console.ReadLine();
50. }
51. For the above code What is the "new" keyword and Which Class Method is
52. called here
A: it will call base class Display method
53. class Token
54. {
55. public virtual string Display()
56. {
57. //Implementation goes here
58. return "base";
59. }
60. }
61. class IdentifierToken:Token
62. {
63. public override string Display() //What is the use of new keyword
64. {
65. //Implementation goes here
66. return "derive";
67. }
68. }
69. static void Method(Token t)
70. {
71. Console.Write(t.Display());
72. }
73. public static void Main()
74. {
75. IdentifierToken Variable=new IdentifierToken();
76. Method(Variable); //Which Class Method is called here
77. Console.ReadLine();
78. }
79. A: Derive
80. In which Scenario you will go for Interface or Abstract Class?
Interfaces, like classes, define a set of properties, methods, and events. But unlike classes, interfaces do not provide implementation. They are implemented by classes, and defined as separate entities from classes. Even though class inheritance allows your classes to inherit implementation from a base class, it also forces you to make most of your design decisions when the class is first published.
Abstract classes are useful when creating components because they allow you specify an invariant level of functionality in some methods, but leave the implementation of other methods until a specific implementation of that class is needed. They also version well, because if additional functionality is needed in derived classes, it can be added to the base class without breaking code.
Interfaces vs. Abstract Classes
Feature Interface Abstract class
Multiple inheritance A class may implement several interfaces. A class may extend only one abstract class.
Default implementation An interface cannot provide any code at all, much less default code. An abstract class can provide complete code, default code, and/or just stubs that have to be overridden.
Constants Static final constants only, can use them without qualification in classes that implement the interface. On the other paw, these unqualified names pollute the namespace. You can use them and it is not obvious where they are coming from since the qualification is optional. Both instance and static constants are possible. Both static and instance intialiser code are also possible to compute the constants.
Third party convenience An interface implementation may be added to any existing third party class. A third party class must be rewritten to extend only from the abstract class.
is-a vs -able or can-do Interfaces are often used to describe the peripheral abilities of a class, not its central identity, e.g. an Automobile class might implement the Recyclable interface, which could apply to many otherwise totally unrelated objects. An abstract class defines the core identity of its descendants. If you defined a Dog abstract class then Damamation descendants are Dogs, they are not merely dogable. Implemented interfaces enumerate the general things a class can do, not the things a class is.
Plug-in You can write a new replacement module for an interface that contains not one stick of code in common with the existing implementations. When you implement the interface, you start from scratch without any default implementation. You have to obtain your tools from other classes; nothing comes with the interface other than a few constants. This gives you freedom to implement a radically different internal design. You must use the abstract class as-is for the code base, with all its attendant baggage, good or bad. The abstract class author has imposed structure on you. Depending on the cleverness of the author of the abstract class, this may be good or bad. Another issue that's important is what I call "heterogeneous vs. homogeneous." If implementors/subclasses are homogeneous, tend towards an abstract base class. If they are heterogeneous, use an interface. (Now all I have to do is come up with a good definition of hetero/homogeneous in this context.) If the various objects are all of-a-kind, and share a common state and behavior, then tend towards a common base class. If all they share is a set of method signatures, then tend towards an interface.
Homogeneity If all the various implementations share is the method signatures, then an interface works best. If the various implementations are all of a kind and share a common status and behavior, usually an abstract class works best.
Maintenance If your client code talks only in terms of an interface, you can easily change the concrete implementation behind it, using a factory method. Just like an interface, if your client code talks only in terms of an abstract class, you can easily change the concrete implementation behind it, using a factory method.
Speed Slow, requires extra indirection to find the corresponding method in the actual class. Modern JVMs are discovering ways to reduce this speed penalty. Fast
Terseness The constant declarations in an interface are all presumed public static final, so you may leave that part out. You can't call any methods to compute the initial values of your constants. You need not declare individual methods of an interface abstract. They are all presumed so. You can put shared code into an abstract class, where you cannot into an interface. If interfaces want to share code, you will have to write other bubblegum to arrange that. You may use methods to compute the initial values of your constants and variables, both instance and static. You must declare all the individual methods of an abstract class abstract.
Adding functionality If you add a new method to an interface, you must track down all implementations of that interface in the universe and provide them with a concrete implementation of that method. If you add a new method to an abstract class, you have the option of providing a default implementation of it. Then all existing code will continue to work without change.
81. see the code
82. interface ICommon
83. {
84. int getCommon();
85. }
86. interface ICommonImplements1:ICommon
87. {
88. }
89. interface ICommonImplements2:ICommon
90. {
91. }
92. public class a:ICommonImplements1,ICommonImplements2
93. {
}
How to implement getCommon method in class a? Are you seeing any problem in the implementation?
Ans:
public class a:ICommonImplements1,ICommonImplements2
{
public int getCommon()
{
return 1;
}
}
94. interface IWeather
95. {
96. void display();
97. }
98. public class A:IWeather
99. {
100. public void display()
101. {
102. MessageBox.Show("A");
103. }
104. }
105. public class B:A
106. {
107. }
108. public class C:B,IWeather
109. {
110. public void display()
111. {
112. MessageBox.Show("C");
113. }
114. }
115. When I instantiate C.display(), will it work?
116. interface IPrint
117. {
118. string Display();
119. }
120. interface IWrite
121. {
122. string Display();
123. }
124. class PrintDoc:IPrint,IWrite
125. {
126. //Here is implementation
127. }
how to implement the Display in the class printDoc (How to resolve the naming Conflict) A: no naming conflicts
class PrintDoc:IPrint,IWrite
{
public string Display()
{
return "s";
}
}
128. interface IList
129. {
130. int Count { get; set; }
131. }
132. interface ICounter
133. {
134. void Count(int i);
135. }
136. interface IListCounter: IList, ICounter {}
137. class C
138. {
139. void Test(IListCounter x)
140. {
141. x.Count(1); // Error
142. x.Count = 1; // Error
143. ((IList)x).Count = 1; // Ok, invokes IList.Count.set
144. ((ICounter)x).Count(1); // Ok, invokes ICounter.Count
145. }
146. }
147. Write one code example for compile time binding and one for run time binding? What is early/late binding?
An object is early bound when it is assigned to a variable declared to be of a specific object type. Early bound objects allow the compiler to allocate memory and perform other optimizations before an application executes.
' Create a variable to hold a new object.
Dim FS As FileStream
' Assign a new object to the variable.
FS = New FileStream("C:\tmp.txt", FileMode.Open)
By contrast, an object is late bound when it is assigned to a variable declared to be of type Object. Objects of this type can hold references to any object, but lack many of the advantages of early-bound objects.
Dim xlApp As Object
xlApp = CreateObject("Excel.Application")
148. Can you explain what inheritance is and an example of when you might use it?
149. How can you write a class to restrict that only one object of this class can be created (Singleton class)?
150. What are the access-specifiers available in c#?
Private, Protected, Public, Internal, Protected Internal.
151. Explain about Protected and protected internal, “internal” access-specifier?
protected - Access is limited to the containing class or types derived from the containing class.
internal - Access is limited to the current assembly.
protected internal - Access is limited to the current assembly or types derived from the containing class.
1) Encapsulation: It is the mechanism that binds together code and data in manipulates, and keeps both safe from outside interference and misuse. In short it isolates a particular code and data from all other codes and data. A well-defined interface controls the access to that particular code and data.
2) Inheritance: It is the process by which one object acquires the properties of another object. This supports the hierarchical classification. Without the use of hierarchies, each object would need to define all its characteristics explicitly. However, by use of inheritance, an object need only define those qualities that make it unique within its class. It can inherit its general attributes from its parent. A new sub-class inherits all of the attributes of all of its ancestors.
3) Polymorphism: It is a feature that allows one interface to be used for general class of actions. The specific action is determined by the exact nature of the situation. In general polymorphism means "one interface, multiple methods", This means that it is possible to design a generic interface to a group of related activities. This helps reduce complexity by allowing the same interface to be used to specify a general class of action. It is the compiler's job to select the specific action (that is, method) as it applies to each situation.
2. What is the difference between a Struct and a Class?
o The struct type is suitable for representing lightweight objects such as Point, Rectangle, and Color. Although it is possible to represent a point as a class, a struct is more efficient in some scenarios. For example, if you declare an array of 1000 Point objects, you will allocate additional memory for referencing each object. In this case, the struct is less expensive.
o When you create a struct object using the new operator, it gets created and the appropriate constructor is called. Unlike classes, structs can be instantiated without using the new operator. If you do not use new, the fields will remain unassigned and the object cannot be used until all of the fields are initialized.
o It is an error to declare a default (parameterless) constructor for a struct. A default constructor is always provided to initialize the struct members to their default values.
o It is an error to initialize an instance field in a struct.
o There is no inheritance for structs as there is for classes. A struct cannot inherit from another struct or class, and it cannot be the base of a class. Structs, however, inherit from the base class Object. A struct can implement interfaces, and it does that exactly as classes do.
o A struct is a value type, while a class is a reference type.
3. Value type & reference types difference? Example from .NET. Integer & struct are value types or reference types in .NET?
Most programming languages provide built-in data types, such as integers and floating-point numbers, that are copied when they are passed as arguments (that is, they are passed by value). In the .NET Framework, these are called value types. The runtime supports two kinds of value types:
• Built-in value types
The .NET Framework defines built-in value types, such as System.Int32 and System.Boolean, which correspond and are identical to primitive data types used by programming languages.
• User-defined value types
Your language will provide ways to define your own value types, which derive from System.ValueType. If you want to define a type representing a value that is small, such as a complex number (using two floating-point numbers), you might choose to define it as a value type because you can pass the value type efficiently by value. If the type you are defining would be more efficiently passed by reference, you should define it as a class instead.
Variables of reference types, referred to as objects, store references to the actual data. This following are the reference types:
• class
• interface
• delegate
This following are the built-in reference types:
• object
• string
4. What is Inheritance, Multiple Inheritance, Shared and Repeatable Inheritance?
**
5. What is Method overloading?
Method overloading occurs when a class contains two methods with the same name, but different signatures.
6. What is Method Overriding? How to override a function in C#?
Use the override modifier to modify a method, a property, an indexer, or an event. An override method provides a new implementation of a member inherited from a base class. The method overridden by an override declaration is known as the overridden base method. The overridden base method must have the same signature as the override method.
You cannot override a non-virtual or static method. The overridden base method must be virtual, abstract, or override.
7. Can we call a base class method without creating instance?
Its possible If its a static method.
Its possible by inheriting from that class also.
Its possible from derived classes using base keyword.
8. You have one base class virtual function how will call that function from derived class?
Ans:
9. class a
10. {
11. public virtual int m()
12. {
13. return 1;
14. }
15. }
16. class b:a
17. {
18. public int j()
19. {
20. return m();
21. }
}
22. In which cases you use override and new base?
Use the new modifier to explicitly hide a member inherited from a base class. To hide an inherited member, declare it in the derived class using the same name, and modify it with the new modifier.
C# Language features
23. What are Sealed Classes in C#?
The sealed modifier is used to prevent derivation from a class. A compile-time error occurs if a sealed class is specified as the base class of another class. (A sealed class cannot also be an abstract class)
24. What is Polymorphism? How does VB.NET/C# achieve polymorphism?
**
25. class Token
26. {
27. public string Display()
28. {
29. //Implementation goes here
30. return "base";
31. }
32. }
33. class IdentifierToken:Token
34. {
35. public new string Display() //What is the use of new keyword
36. {
37. //Implementation goes here
38. return "derive";
39. }
40. }
41. static void Method(Token t)
42. {
43. Console.Write(t.Display());
44. }
45. public static void Main()
46. {
47. IdentifierToken Variable=new IdentifierToken();
48. Method(Variable); //Which Class Method is called here
49. Console.ReadLine();
50. }
51. For the above code What is the "new" keyword and Which Class Method is
52. called here
A: it will call base class Display method
53. class Token
54. {
55. public virtual string Display()
56. {
57. //Implementation goes here
58. return "base";
59. }
60. }
61. class IdentifierToken:Token
62. {
63. public override string Display() //What is the use of new keyword
64. {
65. //Implementation goes here
66. return "derive";
67. }
68. }
69. static void Method(Token t)
70. {
71. Console.Write(t.Display());
72. }
73. public static void Main()
74. {
75. IdentifierToken Variable=new IdentifierToken();
76. Method(Variable); //Which Class Method is called here
77. Console.ReadLine();
78. }
79. A: Derive
80. In which Scenario you will go for Interface or Abstract Class?
Interfaces, like classes, define a set of properties, methods, and events. But unlike classes, interfaces do not provide implementation. They are implemented by classes, and defined as separate entities from classes. Even though class inheritance allows your classes to inherit implementation from a base class, it also forces you to make most of your design decisions when the class is first published.
Abstract classes are useful when creating components because they allow you specify an invariant level of functionality in some methods, but leave the implementation of other methods until a specific implementation of that class is needed. They also version well, because if additional functionality is needed in derived classes, it can be added to the base class without breaking code.
Interfaces vs. Abstract Classes
Feature Interface Abstract class
Multiple inheritance A class may implement several interfaces. A class may extend only one abstract class.
Default implementation An interface cannot provide any code at all, much less default code. An abstract class can provide complete code, default code, and/or just stubs that have to be overridden.
Constants Static final constants only, can use them without qualification in classes that implement the interface. On the other paw, these unqualified names pollute the namespace. You can use them and it is not obvious where they are coming from since the qualification is optional. Both instance and static constants are possible. Both static and instance intialiser code are also possible to compute the constants.
Third party convenience An interface implementation may be added to any existing third party class. A third party class must be rewritten to extend only from the abstract class.
is-a vs -able or can-do Interfaces are often used to describe the peripheral abilities of a class, not its central identity, e.g. an Automobile class might implement the Recyclable interface, which could apply to many otherwise totally unrelated objects. An abstract class defines the core identity of its descendants. If you defined a Dog abstract class then Damamation descendants are Dogs, they are not merely dogable. Implemented interfaces enumerate the general things a class can do, not the things a class is.
Plug-in You can write a new replacement module for an interface that contains not one stick of code in common with the existing implementations. When you implement the interface, you start from scratch without any default implementation. You have to obtain your tools from other classes; nothing comes with the interface other than a few constants. This gives you freedom to implement a radically different internal design. You must use the abstract class as-is for the code base, with all its attendant baggage, good or bad. The abstract class author has imposed structure on you. Depending on the cleverness of the author of the abstract class, this may be good or bad. Another issue that's important is what I call "heterogeneous vs. homogeneous." If implementors/subclasses are homogeneous, tend towards an abstract base class. If they are heterogeneous, use an interface. (Now all I have to do is come up with a good definition of hetero/homogeneous in this context.) If the various objects are all of-a-kind, and share a common state and behavior, then tend towards a common base class. If all they share is a set of method signatures, then tend towards an interface.
Homogeneity If all the various implementations share is the method signatures, then an interface works best. If the various implementations are all of a kind and share a common status and behavior, usually an abstract class works best.
Maintenance If your client code talks only in terms of an interface, you can easily change the concrete implementation behind it, using a factory method. Just like an interface, if your client code talks only in terms of an abstract class, you can easily change the concrete implementation behind it, using a factory method.
Speed Slow, requires extra indirection to find the corresponding method in the actual class. Modern JVMs are discovering ways to reduce this speed penalty. Fast
Terseness The constant declarations in an interface are all presumed public static final, so you may leave that part out. You can't call any methods to compute the initial values of your constants. You need not declare individual methods of an interface abstract. They are all presumed so. You can put shared code into an abstract class, where you cannot into an interface. If interfaces want to share code, you will have to write other bubblegum to arrange that. You may use methods to compute the initial values of your constants and variables, both instance and static. You must declare all the individual methods of an abstract class abstract.
Adding functionality If you add a new method to an interface, you must track down all implementations of that interface in the universe and provide them with a concrete implementation of that method. If you add a new method to an abstract class, you have the option of providing a default implementation of it. Then all existing code will continue to work without change.
81. see the code
82. interface ICommon
83. {
84. int getCommon();
85. }
86. interface ICommonImplements1:ICommon
87. {
88. }
89. interface ICommonImplements2:ICommon
90. {
91. }
92. public class a:ICommonImplements1,ICommonImplements2
93. {
}
How to implement getCommon method in class a? Are you seeing any problem in the implementation?
Ans:
public class a:ICommonImplements1,ICommonImplements2
{
public int getCommon()
{
return 1;
}
}
94. interface IWeather
95. {
96. void display();
97. }
98. public class A:IWeather
99. {
100. public void display()
101. {
102. MessageBox.Show("A");
103. }
104. }
105. public class B:A
106. {
107. }
108. public class C:B,IWeather
109. {
110. public void display()
111. {
112. MessageBox.Show("C");
113. }
114. }
115. When I instantiate C.display(), will it work?
116. interface IPrint
117. {
118. string Display();
119. }
120. interface IWrite
121. {
122. string Display();
123. }
124. class PrintDoc:IPrint,IWrite
125. {
126. //Here is implementation
127. }
how to implement the Display in the class printDoc (How to resolve the naming Conflict) A: no naming conflicts
class PrintDoc:IPrint,IWrite
{
public string Display()
{
return "s";
}
}
128. interface IList
129. {
130. int Count { get; set; }
131. }
132. interface ICounter
133. {
134. void Count(int i);
135. }
136. interface IListCounter: IList, ICounter {}
137. class C
138. {
139. void Test(IListCounter x)
140. {
141. x.Count(1); // Error
142. x.Count = 1; // Error
143. ((IList)x).Count = 1; // Ok, invokes IList.Count.set
144. ((ICounter)x).Count(1); // Ok, invokes ICounter.Count
145. }
146. }
147. Write one code example for compile time binding and one for run time binding? What is early/late binding?
An object is early bound when it is assigned to a variable declared to be of a specific object type. Early bound objects allow the compiler to allocate memory and perform other optimizations before an application executes.
' Create a variable to hold a new object.
Dim FS As FileStream
' Assign a new object to the variable.
FS = New FileStream("C:\tmp.txt", FileMode.Open)
By contrast, an object is late bound when it is assigned to a variable declared to be of type Object. Objects of this type can hold references to any object, but lack many of the advantages of early-bound objects.
Dim xlApp As Object
xlApp = CreateObject("Excel.Application")
148. Can you explain what inheritance is and an example of when you might use it?
149. How can you write a class to restrict that only one object of this class can be created (Singleton class)?
150. What are the access-specifiers available in c#?
Private, Protected, Public, Internal, Protected Internal.
151. Explain about Protected and protected internal, “internal” access-specifier?
protected - Access is limited to the containing class or types derived from the containing class.
internal - Access is limited to the current assembly.
protected internal - Access is limited to the current assembly or types derived from the containing class.
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