This method notifies the server control to perform any necessary prerendering steps prior to saving view state and rendering content .It is generally used by control developers when extending the DetailsView class.
The OnPreRender method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.
Notes to Inheritors:
When overriding OnPreRender in a derived class, be sure to call the base class's OnPreRender method so that registered delegates receive the event.