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property OnStartDock: TStartDockEvent read FOnStartDock write FOnStartDock;


__property TStartDockEvent OnStartDock = {read=FOnStartDock, write=FOnStartDock};


Type Visibility Source Unit Parent
event protected
Vcl.Controls TControl


Occurs when the user begins to drag a control with a DragKind of dkDock.

Use the OnStartDock event handler to implement special processing when the user starts a drag-and-dock operation by dragging the control.

The OnStartDock event handler can create a TDragDockObjectEx object for the DragObject parameter to specify the appearance of the dragging rectangle and how the dragged control interacts with potential docking sites. If you return TDragDockObjectEx as the drag object, there is no need to call the Free method for the DragObject when dragging is over. If you use TDragDockObject, your application is responsible for freeing the drag object.

If the OnStartDock event handler sets the DragObject parameter to nil (Delphi) or NULL (C++), a TDragDockObject object is automatically created.

Note: This information applies to Win32 applications only.

OnStartDock is an event handler of type TStartDockEvent.

See Also