Raising an event invokes the event handler through a delegate. The OnScrollChanged 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.
Note to Inheritors: When overriding OnScrollChanged in a derived class, be sure to call the base class's OnScrollChanged method so that registered delegates receive the event.
Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2