HttpApplication事件执行顺序

Instances of the HttpApplication class are created in the ASP.NET infrastructure, not by the user directly. One instance of the HttpApplication class is used to process many requests in its lifetime; however, it can process only one request at a time. Thus, member variables can be used to store per-request data.

An application executes events that are handled by modules or user code that is defined in the Global.asax file in the following sequence:

1. BeginRequest

2. AuthenticateRequest

3. PostAuthenticateRequest

4. AuthorizeRequest

5. PostAuthorizeRequest

6. ResolveRequestCache

7. PostResolveRequestCache

   After the PostResolveRequestCache event and before the PostMapRequestHandler event, an event handler (a page corresponding to the request URL) is created.

8. PostMapRequestHandler

9. AcquireRequestState

10. PostAcquireRequestState

11. PreRequestHandlerExecute

    The event handler is executed.

12. PostRequestHandlerExecute

13. ReleaseRequestState

14. PostReleaseRequestState

    After the PostReleaseRequestState event, response filters, if any, filter the output.

15. UpdateRequestCache

16. PostUpdateRequestCache

17. EndRequest