'Declaration Protected Friend Overridable Sub OnClosing( _ ByVal e As CancelEventArgs _ )
protected internal virtual void OnClosing( CancelEventArgs e )
Raising an event invokes the event handler through a delegate.
The OnClosing 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 OnClosing in a derived class, be sure to call the base class's OnClosing method so that registered delegates receive the event.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, 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