You want to store some user-specific information in between page postbacks.
Use view state, query string arguments, session state, or a cookie, depending on your needs.
ASP.NET is a stateless programming model. Every time a postback is triggered, your code loads into memory, executes, and is released from memory. If you want to keep track of information after your code has finished processing, you must use some form of state management.
ASP.NET provides several ways to store information, or state, in between requests. The type of state you use determines how long the information will live, where it will be stored, and how secure it will be. Table 15-1 lists the various state options provided ...