The Page and Control Life Cycle

There are several new events for an ASP.NET page:

• LoadComplete , which occurs when the page has finished handling postback data

• PreInit , which occurs before the Init event for controls on the page

• PreLoad , which occurs before the PreLoad event for controls on the page

• PreRenderComplete , which occurs after the PreRender event for all controls on the page

The life cycle of events is shown in Table 9.9. This table covers both public and private events so that the interaction between page and control events can be seen. Page corresponds to a page event, and Ctl corresponds to a control event. New events are shown in bold. The phase and subphase are logical and do not exist as physical events or phasesthey are purely to show the stage in the life cycle. The Adapter Handling column indicates which phases involve the device adapter. (Device adapters are covered in Chapter 10.)

Table 9.9. The Page and Control Life Cycle

Phase	Subphase	Adapter Handling	Event/Method	Notes
Start	Detect postback	Yes	Page.DeterminePostbackMode	If there is no ViewState or the posteventSourceID is empty, an initial request is assumed.
Initialization			Page.PreInit	The place to load Personalization and theme details.
			Page.ApplyControlTheme
			Page.ApplyPersonalization
		Yes	Page.InitCtl.Init
	Begin tracking ViewState		Ctl.TrackViewState
			Page.InitComplete
Load State	Load Control State		Ctl.LoadControlState	For controls that require private state.
	Load ViewState	Yes	Ctl.LoadViewStateRecursive Ctl.LoadViewState	Occurs for each control in the collection.
	Process post data	Yes	Page.ProcessPostData Ctl.LoadPostData	For controls that implement IPost BackDataHandler . First attempt for the RaisePostback event handler.
Load			Page.PreLoad
		Yes	Ctl.LoadRecursive Ctl.Load	Occurs for each control in the collection.
	Process postback	Yes	Page.ProcessPostData Ctl.LoadPostData	For controls that implement IPost BackDataHandler . Second attempt for RaiseChanged events and Post BackEvent .
			RaiseCallbackEvent	If the page or control has a callback event handler.
	Post back events		RaiseChangedEvents RaisePostBackevent
			Page.LoadComplete
Pre-Render	Create child controls		Ctl.EnsureChildControls
		Yes	Ctl.CreateChildControls
			Page.PreRenderComplete Page.SavePersonalizationData
Save State	Save Control State		Ctl.SaveControlState
	Save ViewState		Ctl.SaveViewStateRecursive	Occurs for each control in the collection.
		Yes	Ctl.SaveViewState
Render			Page.CreateMarkupTextWriter Ctl.RenderControl Ctl.Render Ctl.RenderChildren
Unload			Page.UnLoadRecursive Ctl.UnLoadRecursive Ctl.Unload	Occurs for each control in the collection.
		Yes	Page.UnLoad
	Dispose		Ctl.Dispose