Application state management in ASP.NET

A new instance of the Web page class is created each time the page is posted to the server. In traditional Web programming, this would typically mean that all information associated with the page and the controls on the page would be lost with each round trip. For example, if a user enters information into a text box, that information would be lost in the round trip from the browser or client device to the server.

To overcome this inherent limitation of traditional Web programming, ASP.NET includes several options that help you preserve data on both a per-page basis and an application-wide basis. These features are as follows:

• View state

• Control state

• Hidden fields

• Cookies

• Query strings

• Application state

• Session state

• Profile Properties

  For more detail read this article

  http://www.c-sharpcorner.com/UploadFile/freelance91/ASPNETstatemanagementtechniques01012007212655PM/ASPNETstatemanagementtechniques.aspx