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How to Detect the Start MoveResize, Move and Stop MoveResize events of a Delphi Form

Title: How to Detect the Start Move/Resize, Move and Stop Move/Resize events of a Delphi Form If you want to detect when a user starts resizing and moving a Delphi form, and when the move (or resize) operation is finished, you need to handle a few Windows messages. The WM_ENTERSIZEMOVE message is sent once to a window when it enters the moving or sizing mode. The WM_EXITSIZEMOVE message is sent once to a window after it has exited the moving or sizing mode. While a form is being moved, the WM_MOVE message is sent to a window. Here's an example (move this form and watch its title): ~~~~~~~~~~~~~~~~~~~~~~~~~ type TForm1 = class(TForm) private procedure WMEnterSizeMove(var Message: TMessage) ; message WM_ENTERSIZEMOVE; procedure WMMove(var Message: TMessage) ; message WM_MOVE; procedure WMExitSizeMove(var Message: TMessage) ; message WM_EXITSIZEMOVE; ... procedure TForm1.WMEnterSizeMove(var Message: TMessage) ; begin Caption := 'Move / resize started'; end; (*WMEnterSizeMove*) procedure TForm1.WMMove(var Message: TMessage) ; begin Caption := Format('Form is being moved. Client area x: %d, y:%d', [TWMMove(Message).XPos,TWMMove(Message).YPos]) ; end; (*WMMove*) procedure TForm1.WMExitSizeMove(var Message: TMessage) ; begin ShowMessage('Move / resize complete!') ; end; (*WMExitSizeMove*) ~~~~~~~~~~~~~~~~~~~~~~~~~ More Form related tips and article.