Event-Handling Method Description
Application_Start() Occurs when the application starts
which is the first time it receives a request from any user.
Application_End() Occurs when the application is shutting down, generally because the web server is being restarted.
Application_BeginRequest() Occurs with each request the application receives, just before the page code is executed.
Application_EndRequest() Occurs with each request the application receives, just after the page code is executed.
Session_Start() Occurs whenever a new user request is received and a session is started.
Session_End() Occurs when a session times out or is programmatically ended.
Application_Error() Occurs in response to an unhandled error.