Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
Raising an event invokes the event handler through a delegate. For more information, see Handling and Raising Events.
The 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
Inheriting classes should override this method to handle the Windows request to erase the background.