Most asked Interview Questions on .NET

1. Describe the role of inetinfo.exe, aspnet_isapi.dll andaspnet_wp.exe in the page loading process.

inetinfo.exe is theMicrosoft 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 tothe actual worker process aspnet_wp.exe.

2. What’s the difference between Response.Write() andResponse.Output.Write()?

The latter one allows you to write formattedoutput.

3. What methods are fired during the page load?

Init() - when the pageis instantiated, Load() - when the page is loaded into server memory,PreRender() - the brief moment before the page is displayed to the user asHTML, Unload() - when page finishes loading.

4. Where does the Web page belong in the .NET Framework class hierarchy?

System.Web.UI.Page

5. Where do you store the information about the user’s locale? System.Web.UI.Page.Culture

6. What’s the difference between Codebehind="MyCode.aspx.cs" andSrc="MyCode.aspx.cs"?

CodeBehind is relevant to Visual Studio.NET only.

7. What’s a bubbled event?

When you have a complex control, like DataGrid, writing an event processing routine for each object (cell, button, row, etc.) is quite tedious. The controls can bubble up their eventhandlers, allowing the main DataGrid event handler to take care of its constituents.

8. Suppose you want a certain ASP.NET function executed on MouseOver overa certain button. Where do you add an event handler?

It’s the Attributesproperty, the Add function inside that property. So btnSubmit.Attributes.Add("onMouseOver","someClientCode();")

9. What data type does the RangeValidator control support?

Integer,String and Date.

10. Explain the differences between Server-side and Client-side code?

Server-side code runs on the server. Client-side code runs in the clients’ browser.

11. What type of code (server or client) is found in a Code-Behind class?
Server-side code.

12. Should validation (did the user enter a real date) occur server-side or client-side? Why?

Client-side. This reduces an additional request to the server to validate the users input.

13. What does the "EnableViewState" property do? Why would I want it on or off?

It enables the viewstate on the page. It allows the page to save the users input on a form.

14. What is the difference between Server.Transfer and Response.Redirect? Why would I choose one over the other?

Server.Transfer is used to post a form to another page. Response.Redirect is used to redirect the user to another page or site.

15. Can you explain the difference between an ADO.NET Dataset and an ADO Recordset?

· A DataSet can represent an entire relational database in memory, complete with tables, relations, and views.

· A DataSet is designed to work without any continuing connection to the original data source.

· Data in a DataSet is bulk-loaded, rather than being loaded on demand.

· There's no concept of cursor types in a DataSet.

· DataSets have no current record pointer You can use For Each loops to move through the data.

· You can store many edits in a DataSet, and write them to the original data source in a single operation.

· Though the DataSet is universal, other objects in ADO.NET come in different versions for different data sources.

16. Can you give an example of what might be best suited to place in the Application_Start and Session_Start subroutines?

This is where you can set the specific variables for the Application and Session objects.

17. If I’m developing an application that must accommodate multiple security levels though secure login and my ASP.NET web application is spanned across three web-servers (using round-robin load balancing) what would be the best approach to maintain login-in state for the users?

Maintain the login state security through a database.

18. Can you explain what inheritance is and an example of when you might use it?

When you want to inherit (use the functionality of) another class. Base Class Employee. A Manager class could be derived from the Employee base class.

19. Whats an assembly?

Assemblies are the building blocks of the .NET framework. Overview of assemblies from MSDN

20. Describe the difference between inline and code behind.

Inline code written along side the html in a page. Code-behind is code written in a separate file and referenced by the .aspx page.

21. Explain what a diffgram is, and a good use for one?

The DiffGram is one of the two XML formats that you can use to render DataSet object contents to XML. For reading database data to an XML file to be sent to a Web Service.

22. Whats MSIL, and why should my developers need an appreciation of it if at all?

MSIL is the Microsoft Intermediate Language. All .NET compatible languages will get converted to MSIL.

23. Which method do you invoke on the DataAdapter control to load your generated dataset with data?

The .Fill() method

24. Can you edit data in the Repeater control?

No, it just reads the information from its data source

25. Which template must you provide, in order to display data in a Repeater control?

ItemTemplate

26. How can you provide an alternating color scheme in a Repeater control?
Use the AlternatingItemTemplate

27. 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?
You must set the DataSource property and call the DataBind method.

28. What base class do all Web Forms inherit from?

The Page class.

29. Name two properties common in every validation control?
ControlToValidate property and Text property.

30. What tags do you need to add within the asp:datagrid tags to bind columns manually?

Set AutoGenerateColumns Property to false on the datagrid tag

31. What tag do you use to add a hyperlink column to the DataGrid?

32. What is the transport protocol you use to call a Web service?

SOAP is the preferred protocol.

33. True or False: A Web service can only be written in .NET?

False

34. What does WSDL stand for?

(Web Services Description Language)

35. Where on the Internet would you look for Web services?
(http://www.uddi.org)

36. Which property on a Combo Box do you set with a column name, prior to setting the DataSource, to display data in the combo box?

DataTextField property

37. Which control would you use if you needed to make sure the values in two different controls matched?

CompareValidator Control

38. True or False: To test a Web service you must create a windows application or Web application to consume this service?

False, the webservice comes with a test page and it provides HTTP-GET method to test.

39. How many classes can a single .NET DLL contain?

It can contain many classes.

Adding or Substracting Date time in VB.NET

While it has become common practice for developers to manipulate VB.NET date/time values manually, it's never a good idea because the result is rarely a correct date/time value. Whenever you try to use your own calculation routines for adding and subtracting date/time values, you risk generating a bug since it's hard to check the code for all possible outcomes, whereas utilizing appropriate .NET objects and methods is sure to provide correct results.

As you can see here

Private Sub AddDateTime()


Dim dtNow As Date = Now()
MsgBox(dtNow)


dtNow = dtNow.AddYears(20)
MsgBox(dtNow) the Date object provides for simple manipulation that allows you to add and subtract date/time values in VB.NET.


dtNow = dtNow.AddMonths(10)
MsgBox(dtNow)


dtNow = dtNow.AddDays(3)
MsgBox(dtNow)


dtNow = dtNow.AddHours(5)
MsgBox(dtNow)


dtNow = dtNow.AddMinutes(2)
MsgBox(dtNow)


dtNow = dtNow.AddSeconds(6)
MsgBox(dtNow)


dtNow = dtNow.AddMilliseconds(4)
MsgBox(dtNow)


dtNow = dtNow.AddYears(-2)
MsgBox(dtNow)


End Sub

the Date object provides for simple manipulation, which allows you to add and subtract date/time values in VB.NET. In the example, I define the Date variable dtNow and set it to the current date/time value. I utilize these Date object methods to manipulate the date: AddYears, AddMonths, AddDays, AddHours, AddMinutes, AddSeconds, and AddMilliseconds. For each method, I specify the number of years or months or hours to add. Subtraction is done by passing a negative value to the method. Notice that these methods will never result in an impossible date; manual manipulation cannot guarantee such results.

Increase timeout in dataset

Tuning your SQL queries for the best performance can be part of life when you’re writing a database application. Sometimes life is hard, and you just can’t get things running as quickly as you’d like. With the default command time-out at 30 seconds, how do you use a TableAdapter to execute methods without timing out and failing? Turns out, it’s pretty easy. If you have a DataSet called MyDataSet.xsd, add code to the MyDataSet.vb partial class file:

Imports System.Data.SqlClient
Namespace MyDataSetTableAdapters
    Partial Class CustomersTableAdapter
        Public Sub SetCommandTimeOut(ByVal timeOut As Integer)
            For Each command As SqlCommand In Me.CommandCollection
                command.CommandTimeout = timeOut
            Next
        End Sub
    End Class
End Namespace

When it comes time to call a long query, just call the SetCommandTimeOut method before the query:

Dim ds As New MyDataSet
Dim customersTA As New MyDataSetTableAdapters.CustomersTableAdapter
' Increase time-out to 60 seconds
customersTA.SetCommandTimeOut(60000)
' Do the slow query
customersTA.FillSlowQuery(ds.Customers)

This will change the time-out for all of the commands on the instance of the TableAdapter, so be sure to set it back to a lower value once you’re done with the long query

Hopefully you'll find my first post useful!<

Firefox Speedup tips

** Your Comments Appreciated!!!!

Hide Files in an Image.

Here are simple steps to hide files in images.

1. Gather all the files that you wish to hide in a folder anywhere in your PC (For Example:- If the files are in C:\temp).

2. Now, add those files in a RAR archive (e.g. secret.rar). This file should also be in the same directory (C:\temp).

3. Now, look for a simple JPEG picture file (e.g. logo.jpg). Copy/Paste that file also in C:\temp.

4. Now, open Command Prompt (Go to Run and type ‘cmd‘). Make your working directory C:\temp.

5. Now type: “COPY /b logo.jpg + secret.rar output.jpg” (without quotes) - Now, logo.jpg is the picture you want to show, secret.rar is the file to be hidden, and output.jpg is the file which contains both.

6. Now, after you have done this, you will see a file output.jpg in C:\temp. Open it (double-click) and it will show the picture you wanted to show. Now try opening the same file with WinRAR, it will show the hidden archive .

Do you Believe in Shiridi sai baba ?

Hi Friends,

Here is a website where you can ask saibaba a question and he will answer you. If you have belief in shri Shiridi SaiBaba then you might be aware of a book which will have all the answers of saibaba and you randomly take a page and choose the solution.Please click the link below to findout more and try it!

Ask sri sai baba

Sql Problem.

Hi Friends,

Today i have experienced a wierd problem with the stored procedure on my Sql server 2005. The stored procedure works fine for some time and later on it gives me a time out.But when i try to recompile the stored procedure it works fine. I thought to find a permanent solution for this. I have found some solution which works for now. I have to check if this problem is solved or it still persists.
I will update the blog if this worked.

1)DBCC FREEPROCCACHE --this flushes out the procedure caches
2)DBCC FLUSHPROCINDB (dbid) --recompiles all SPs in the database

In order to get the dbid we can use a simple select statement as shown below.


SELECT DB_ID('databasename') as [Database ID].

**Keep checking the blog for updates.