How could I implement a trap to indicate ASP.Net Session expiry

I need to create a user login/logout/Session expiry tracking page(ASP.Net).开发者_如何学Python. It is obvious that I can invoke my tracking page when user logs in and logs out.. How do I detect session expirey ?

Your most obvious way in a stateful app is to assume that any hit on a non-login page without being logged in implies that the session has expired.

use the Session_End event in Global.asax. Keep in mind this event does not fires when sessions are persisted outside of the process (in SQL for example)