In Asp.net what would you put in the Session_Start and Session_End events in Global.asax ?

Question

If not code could you please provide some generic explanation?

Answer 1

The most common example is counting the online users. Incrementing the count on Session_Start and the opposite on Session_End.

Answer 2

Session_Start Collection all user information and storing in database. Preparing system for user like temporary file, cached file.

Session_End Saving user state in database. Cleaning system and etc.

Answer 3

In Session_Start you can setup anything relevant for a session, depends very much on the application.

In general you should avoid Session_End if possible, not only will it generally fire very late (after a session timeout) but in a multi-server configurations it will not fire at all.

For details, see the SessionState tag in Web.config

Answer 4

It's always good to remind ourselves why we should never use Session_End

excert from Understanding session state modes + FAQ

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1. Session_End event is only supported in InProc mode.
2. Session_End won't be fired if you close your browser. HTTP is a stateless protocol, and the server has no way of knowing if the browser has closed or not.
3. Session_End will be fired only:
   (a). After n minutes of inactivity (n = timeout value),
   or
   (b). If someone calls Session.Abandon().
   
4. For case (a) (Point 3), Session_End will be run by a background thread, which implies: (a). Your code in Session_End is running using the worker process account. You may have permission problem if you're accessing resource such as database. (b). If an error happens in Session_End, it will fail silently.
5. For case (b) (Point 3), in order for Session_End to be fired, your session state has to exist first. That means you have to store some data in the session state and has completed at least one request.
6. Again for case (b) (Point3), Session_End will be called only if the abandoned session is actually found. As a result, if you create and abandon a session inside the same request, because the session hasn't been saved and thus can't be found, Session_End won't be called. This is a bug in .NET Framework 1.0 and 1.1.