Drag and Drop an Image on a form?

[bill0287]

I want to be able to drag a image across the form and drop it, like you might do in a solitaire game. I am using this wiki as guidance but not having any luck:

http://wiki.freepascal.org/Drag_and_Drop_sample

1. I set the Dragmode on the image and the form to dmAutomatic
2. I set the image OnMouseDown even to start the drag

When I click on the image nothing happens so I must be missing something.

Here is the test code:

Code: Pascal  [Select][+][-]

1. unit main;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, ExtCtrls;
9.  
10. type
11.  
12.   { TForm1 }
13.  
14.   TForm1 = class(TForm)
15.     Image1: TImage;
16.     procedure FormDragOver(Sender, Source: TObject; X, Y: Integer;
17.       State: TDragState; var Accept: Boolean);
18.     procedure Image1MouseDown(Sender: TObject; Button: TMouseButton;
19.       Shift: TShiftState; X, Y: Integer);
20.   private
21.     { private declarations }
22.   public
23.     { public declarations }
24.   end;
25.  
26. var
27.   Form1: TForm1;
28.  
29. implementation
30.  
31. {$R *.lfm}
32.  
33. { TForm1 }
34.  
35. procedure TForm1.Image1MouseDown(Sender: TObject; Button: TMouseButton;
36.   Shift: TShiftState; X, Y: Integer);
37. begin
38.     if Button = mbLeft then   {check if left mouse button was pressed}
39.       Image1.BeginDrag(true);  {starting the drag operation}
40. end;
41.  
42. procedure TForm1.FormDragOver(Sender, Source: TObject; X, Y: Integer;
43.   State: TDragState; var Accept: Boolean);
44. begin
45.   Accept := true;
46. end;
47.  
48. end.
49.  

[balazsszekely]

Try this:

Code: Pascal  [Select][+][-]

1.  TForm1 = class(TForm)
2.  //...
3.   private
4.     dX: Integer;
5.     dY: Integer;
6.     { private declarations }
7.   public
8.     { public declarations }
9.   end;    
10.  
11. //...
12.  
13. [code=pascal]
14. procedure TForm1.Image1MouseDown(Sender: TObject; Button: TMouseButton;
15.   Shift: TShiftState; X, Y: Integer);
16. begin
17.   if Button = mbLeft then
18.   begin
19.     dX := X;
20.     dY := Y;
21.     Image1.BeginDrag(true);
22.   end;
23. end;
24.  
25. procedure TForm1.FormDragOver(Sender, Source: TObject; X, Y: Integer;
26.   State: TDragState; var Accept: Boolean);
27. begin
28.   Accept := True;
29. end;
30.  
31. procedure TForm1.FormDragDrop(Sender, Source: TObject; X, Y: Integer);
32. begin
33.   Image1.Left := X - dX;
34.   Image1.Top := Y - dY;
35. end;    
36.  

[bill0287]

That definitely works, thanks.