How to: Read Values from Application State
Application state is a data repository that is available to all classes within an ASP.NET application. Application state is stored in memory on the server and is faster than storing and retrieving data in a database. Unlike session state, which is specific to a single user session, application state applies to all users and sessions. Therefore, application state is a useful place to store small amounts of often-used data that does not change from one user to another.
Application state is stored in theclass, a new instance of which is created the first time a user accesses a URL resource within an application. For more information, see .
Application state stores data typed as. Therefore, even though you do not have to serialize the data when storing it in application state, you must cast the data to the appropriate type when retrieving it. Although you can cast a null (Nothing in Visual Basic) object, if you attempt to use a non-existent application-state entry in some other way (for example, to examine its type), a exception is thrown.
To read a value from application state
Determine whether the application variable exists, and then convert the variable to the appropriate type when you access it.
The following code example retrieves the application state
AppStartTimevalue and converts it to a variable named
appStateTimeof type .
If (Not Application("AppStartTime") Is Nothing) Then Dim myAppStartTime As DateTime = _ CDate(Application("AppStartTime")) End If