Can dataset be stored in a viewstate?

Yes, a dataset may be stored in a viewstate. However, a viewstate is passed to the server as a hidden variable. Precaution should be taken that the dataset size is not too big, otherwise such an activity will take a toll on both the client and server system resources, and ultimately slow down rendering of the data on the client system. Also note that the viewstate data may not be sent to another aspx page, as thats a limitation of a viewstate object.

What file extension does ASP.NET use for Web Services?

ASP.NET uses the .aspx extension for Web Service files.

Can two different programming languages be mixed in a single ASPX file?

ASP.NET’s built-in parsers are used to remove code from ASPX files and create temporary files. Each parser understands only one language. Therefore mixing of languages in a single ASPX file is not possible.

How many ViewState objects can be created on an aspx page ?

There is no limit. You can have any number of ViewState object on single aspx page. However more Viewstate objects, more slowly it loads.

Describe the difference between inline and code behind. which is best in a loosely coupled solution?

ASP.NET supports two modes of page development: Page logic code that is written inside runat=”server”> blocks within an .aspx file and dynamically compiled the first time the page is requested on the server. Page logic code that is written within an external class that is compiled prior to deployment on a server and linked “”behind”” the .aspx file at run time.

Describe the difference between inline and code behind.

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

What are partial Class?

Partial class are new feature in 2.0 Framework where single class is split among N-number of files,this is useful when more than one developer wants to work on a same class,through class is split into N-number of files only one constructor will exist among all class files.When CLR complies the partial class after seeing Partial keyword CLR checks for class with same name and combines all partial class and compile it.
Example for partial class are all ASPX pages