http://msdn.microsoft.com/en-us/library/ms973868
Global.asax
The Global.asax file is similar to the Global.asa file in ASP, albeit that there are many more events available in ASP.NET. Also, Global.asax is compiled instead of interpreted as it is in ASP. You still have event procedures that fire within the Global.asax file when certain events happen on your Web site. In the following list, you will find the event procedures that are available to you within the Global.asax file.
Table 4. Event procedures available within Global.asax
| Event Procedure | Description |
|---|---|
| Application_Start | Fires when the first user hits your Web site |
| Application_End | Fires when the last user in the site's session times out |
| Application_Error | Fires when an unhandled error occurs in the application |
| Session_Start | Fires when any new user hits your Web site |
| Session_End | Fires when a user's session times out or ends |
| Application_AcquireRequestState | Fires when ASP.NET acquires the current state (for example, session state) associated with the current request |
| Application_AuthenticateRequest | Fires when a security module establishes the identity of the user |
| Application_AuthorizeRequest | Fires when a security module verifies user authorization |
| Application_BeginRequest | Fires when ASP.NET starts to process the request, before other per-request events |
| Application_Disposed | Fires when ASP.NET completes the chain of execution when responding to a request |
| Application_EndRequest | Fires as the last event during the processing of the request, after other pre-request events |
| Application_PostRequestHandlerExecute | Fires right after the ASP.NET handler (page, XML Web service) finishes execution |
| Application_PreRequestHandlerExecute | Fires just before ASP.NET begins executing a handler such as a page or XML Web service |
| Application_PreSendRequestContent | Fires just before ASP.NET sends content to the client |
| Application_PreSendRequestHeaders | Fires just before ASP.NET sends HTTP headers to the client |
| Application_ReleaseRequestState | Fires after ASP.NET finishes executing all request handlers. This event causes state modules to save the current state data |
| Application_ResolveRequestCache | Fires after ASP.NET completes an authorization event to let the caching modules serve requests from the cache, bypassing execution of the handler (the page or Web service, for example). |
| Application_UpdateRequestCache | Fires after ASP.NET finishes executing a handler in order to let caching modules store responses that will be used to serve subsequent requests from the cache |