Assembly: System.Web (in system.web.dll)
The OnPreRender method is overridden to register for postback. If client script is enabled, it also renders the necessary script and hidden fields.
Raising an event invokes the event handler through a delegate. For more information, see Consuming Events.
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 the OnPreRender method in a derived class, be sure to call the OnPreRender method for the base class so that registered delegates receive the event.