This member overrides Control.OnPreRender(EventArgs), and more complete documentation might be available in that topic.
Raises the PreRender event.
Assembly: System.Web (in System.Web.dll)
The PreRender event is used to perform any updates before the output for the server control is rendered to the page. Any changes in the view state of the server control can be saved during this event. Such changes made in the rendering phase are not saved.