1. 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 event handlers, allowing the main DataGrid event handler to take care of its constituents.

2. What is the Global.asax used for?

The Global.asax (including the Global.asax.cs file) is used to implement application and session level events.

3. 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.  A good use is reading database data to an XML file to be sent to a Web Service.

4. What are the different types of assemblies available and their purpose?

Private, Public/shared and Satellite Assemblies.

5. What is CLS (Common Language Specificaiton)?

It provides the set of specificaiton which has to be adhered by any new language writer / Compiler writer for .NET Framework. This ensures Interoperability. For example: Within a ASP.NET application written in C#.NET language, we can refer to any DLL written in any other language supported by .NET Framework. As of now .NET Supports around 32 languages.

6. What methods are fired during the page load? Init()

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

7. Whats an assembly?

Assemblies are the building blocks of the .NET framework.

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

ItemTemplate

9. What’s the difference between Codebehind="MyCode.aspx.cs" and Src="MyCode.aspx.cs"?

CodeBehind is relevant to Visual Studio.NET only.

10. What is ViewState?

ViewState allows the state of objects (serializable) to be stored in a hidden field on the page.  ViewState is transported to the client and back to the server, and is not stored on the server or any other external source.  ViewState is used to retain the state of server-side objects between post backs.

11. What is Boxing and UnBoxing?

Boxing is implicit conversion of ValueTypes to Reference Types (Object).

UnBoxing is explicit conversion of Reference Types (Object) to its equivalent ValueTypes. It requires type-casting.

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

Server.Transfer  transfers page processing from one page directly to the next page without making a round-trip back to the client's browser.  This provides a faster response with a little less overhead on the server.  Server.Transfer does not update the clients url history list or current url. 

Response.Redirect  is used to redirect the user's browser to another page or site.  This perform as a trip back to the client where the client's browser is redirected to the new page.  The user's browser history list is updated to reflect the new address.

13. What’s the difference between Response.Write() and Response.Output.Write()?

Response.Output.Write() allows you to write formatted output.

14. What are user controls and custom controls?

Custom controls :  A control authored by a user or a third-party software vendor that does not belong to   the .NET Framework class library. This is a generic term that includes user controls. A  custom server control is used in Web Forms (ASP.NET pages). A custom client control is used  in Windows Forms applications.

User Controls : In ASP.NET: A user-authored server control that enables an ASP.NET page to be re-used   as a server control. An ASP.NET user control is authored declaratively  and persisted as a  text file with an .ascx extension. The ASP.NET page framework compiles a user control on  the fly to a class that derives from the System.Web.UI.UserControl class.

15. What are the different types of Session state management options available with ASP.NET?

ASP.NET provides In-Process and Out-of-Process state management. 

In-Process  stores the session in memory on the web server.  This requires the a "sticky-server" (or no load-balancing) so that the user is always reconnected to the same web server. 

Out-of-Process  Session state management stores data in an external data source.  The external data source may be either a SQL Server or a State Server service.  Out-of-Process state management requires that all objects stored in session are serializable.