Have you ever wondered about all the stages that an ASP.NET request goes through? Ever wonder why it is such a performance hit to have a wildcard mapping to map all extensions on your web server to ASP.NET? This information corresponds to IIS 5.0 and 6.0. For information on the life cycle in IIS 7.0, see ASP.NET Application Life Cycle Overview for IIS 7.0. You can also check out the ASP.NET Page Life Cycle Overview for information on what happens once a page is run.
User requests a resource
A request comes into the web server and it will check to see what is mapped to handle the request. ASP.NET is an ISAPI extension under the web server.
ASP.NET receives the first request for an application
ASP.NET will first create the application domain for this application. These allow each application to be isolated from each other. ASP.NET then compiles all the top-level items in the application, if required, including the App_Code folder.
ASP.NET core objects created for the request
ASP.NET will create the Request, Response, and Go to the complete details ...