When notified by this method, server controls must perform any initialization steps that are required to create and set up an instance. In this stage of the server control's lifecycle, the control's view state has yet to be populated. Additionally, you cannot access other server controls when this method is called either, regardless of whether it is a child or parent to this control. Other server controls are not certain to be created and ready for access.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)