User Control Life cycle

Event Phase	Description	Method or event to override
Initialize	Initialize settings needed during the lifetime of the incoming Web request.	Init event (OnInit method)
Load view state	At the end of this phase, the ViewState property of a control is automatically populated. A control can override the default implementation of the LoadViewState method to customize state restoration.	LoadViewState method
Load	Perform actions common to all requests, such as setting up a database query. At this point, server controls in the tree are created and initialized, the state is restored, and form controls reflect client-side data.	Load event (OnLoad method)
Handle postback events	Handle the client-side event that caused the postback and raise appropriate events on the server. Note Only controls that process postback events participate in this phase.	RaisePostBackEvent method
Prerender	Perform any updates before the output is rendered. Any changes made to the state of the control in the prerender phase can be saved, while changes made in the rendering phase are lost.	PreRender event (OnPreRender method)
SaveViewState	The ViewState property of a control is automatically persisted to a string object after this stage. This string object is sent to the client and back as a hidden variable. For improving efficiency, a control can override the SaveViewState method to modify the ViewState property.	SaveViewState method
Render	Generate output to be rendered to the client.	Render method
Dispose	Perform any final cleanup before the control is torn down. References to expensive resources such as database connections must be released in this phase.	Dispose method
Unload	Perform any final cleanup before the control is torn down. Control authors generally perform cleanup in Dispose and do not handle this event.	UnLoad event (On UnLoad