'Declaration Protected Overridable Function OnCategoryAdding( _ ByVal category As DiagramToolboxCategory _ ) As Boolean
protected virtual bool OnCategoryAdding( DiagramToolboxCategory category )
true
adding of the category should be cancelled.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