Making A Draggable Titlebar

unit Unit1; interface uses Windows, Classes, Controls, Forms, StdCtrls; type TForm1 = class(TForm) Label1: TLabel; procedure Label1MouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer); procedure Label1MouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer); private { Private declarations } public { Public declarations } end; var Form1: TForm1; X_pos: Integer; Y_pos: Integer; implementation {$R *.DFM} procedure TForm1.Label1MouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer); begin X_pos := X; Y_pos := Y; end; procedure TForm1.Label1MouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer); begin if HiWord(GetAsyncKeyState(VK_LBUTTON)) > 0 then begin Form1.Left := Form1.Left + X - X_pos; Form1.Top := Form1.Top + Y - Y_pos; end; end; end.

Comments

Draggable titlebars of this kind are  most useful in cases where you have a form without a titlebar, but still need to be able to drag the form.  Use a Label and position and size it where you want the draggable 'hook' to be.  If you wish, set the Label as transparent, and leave the Caption empty; and remember to set the Label's Autosize as false.

In this example we show the attachment to a Label; however, the same technique may be applied to most controls with MouseMove and MouseDown events.  See also: Making a Draggable Form.

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