The life cycle begins with a request for the page, which causes the server to load it. When the request is complete, the page is unloaded. The life cycle of a page is marked by the following events:
Initialize: Initialize is the first phase in the life cycle for any page or control. It is here that any settings needed for the duration of the incoming request are initialized.
Load ViewState: The ViewState property of the control is populated. The ViewState information comes from a hidden variable on the control, used to persist the state across round trips to the server. The input string from this hidden variable is parsed by the page framework, and the ViewState property is set. This can be modified via the LoadViewState( ) method: This allows ASP.NET to manage the state of your control across page loads so that each control is not reset to its default state each time the page is posted.
Process Post back Data: During this phase, the data sent to the server in the posting is processed. If any of this data results in a requirement to update the ViewState, that update is performed via the LoadPostData ( ) method.
Load: CreateChildControls ( ) is called, if necessary, to create and initialize server controls in the control tree. State is restored, and the form controls show client-side data. You can modify the load phase by handling the Load event with the OnLoad method.
Send Postback Change Modifications: If there are any state changes between the current state and the previous state, change events are raised via the RaisePostDataChangedEvent( ) method.
Handle Postback Events: The client-side event that caused the postback is handled.
PreRender: This is the phase just before the output is rendered to the browser. It is essentially your last chance to modify the output prior to rendering using the OnPreRender ( ) method.
Save State: Near the beginning of the life cycle, the persisted view state was loaded from the hidden variable. Now it is saved back to the hidden variable, persisting as a string object that will complete the round trip to the client. You can override this using the SaveViewState () method.
Render: This is where the output to be sent back to the client browser is generated. You can override it using the Render method. CreateChildControls ( ) is called, if necessary, to create and initialize server controls in the control tree.
Dispose: This is the last phase of the life cycle. It gives you an opportunity to do any final cleanup and release references to any expensive resources, such as database connections. You can modify it using the Dispose ( ) method.