An Overview of ASP.NET Architecture

Application Life Cycle Events

• IIS Picks up the request


• IIS looks for the server extension


• If the extension is .aspx then IIS maps the request into aspnet_isapi.dll


• aspnet_isapi.dll hosts an ASP.NET worker process that creates an HTTP Pipeline


• The Http Pipeline object hosts objects like HttpRuntime, HttpApplicationFactory, and HttpWorkerRequest


• The HttpApplicationFactory either creates a new HttpApplication or selects an existing one from the pool of applications
  


• The appropriate PageHandlerFactory will be called

Page Life Cycle Events
The events that are executed in the life cycle of the page

• Page_Init (Create Page Controls and initialize them)


• LoadViewState (Restores the view state of the page)


• LoadPostData (Populates the controls with previously posted data)


• Page_Load (To bind data from database to controls)


• RaisePostDataChangedEvent


• RaisePostBackEvent (It is only raised if there is a postback)


• Page_PreRender (Right before rendering)


• SaveViewState


• Page_Render


• Page_UnLoad

We can write custom handlers to override these events

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