Work done before Asp.net pageload

First, IIS receives the request and sends it to ASP. NET.
The first thing ASP. NET does is to create an httpcontext object.
Then, httpapplication starts to take over.
The first is to trigger the beginrequest event.
Then, authenticate
Then authorize
Then create the state, that is, the session.
Then there are cache and other policies.
Then execute ihttphandler, usually page.
Now the control is handed over to page.
If the aspx file has not been compiled, it is first compiled into a page class.
Page first triggers the preinit event
Then apply themes
Then, the viewstate of all controls is restored, the init event is triggered, and the init event of all controls is triggered.
Then the initcomplete event is triggered.
Then, the preload event is triggered.
Then, the load event is triggered to trigger the load events of all controls.
Next is loadcomplete.
Then, the prerender triggers the prerender events of all controls.
Then, prerendercomplete
Then start render HTML code
The last is unload, which triggers the unload events of all controls.
Then the page is finished.
Return it to httpapplication.
The last event triggered by httpapplication is endrequest.
At this time, ASP. NET is finished.
Return work to IIS.