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Jeff
Jeff

Reputation: 12163

Getting a Form's Icon when I know the Form's handle

I am trying to get the Icon of a form, and set it to my own app's Icon. I found this code, however it does not really work for me:

  MyIcon := TIcon.Create;
   Try
   MyIcon.Handle := MyHandle;
   MyForm.Icon := MyIcon;
   Finally
     MyIcon.Free;
   End;
 end;

I tried opening an app that I know has a specific Icon, I find it's handle, but the Icon that is shown in my app, is the default Windows exe one.

Any ideas?

Upvotes: 0

Views: 688

Answers (1)

Andreas Rejbrand
Andreas Rejbrand

Reputation: 108948

To answer the question in the title of your post:

To obtain a TIcon from a HWND, that is, to obtain the icon associated with a window (not necessarily in your own application), do something like

procedure TForm1.FormClick(Sender: TObject);
var
  HIco: HICON;
  Icon: TIcon;
begin
  HIco := SendMessage(Handle, WM_GETICON, ICON_BIG, 0);
  if HIco = 0 then
    HIco := SendMessage(Handle, WM_GETICON, ICON_SMALL2, 0);
  Icon := TIcon.Create;
  try
    Icon.ReleaseHandle;
    Icon.Handle := HIco;
    // Do something with Icon, for instance
    Canvas.Draw(10, 10, Icon);
  finally
    Icon.Free;
  end;
end;

To use the icon of the HWND window as the icon of your own form, do

procedure TForm1.FormClick(Sender: TObject);
var
  HWin: HWND;
  HIco: HICON;
begin
  HWin := FindWindow(nil, 'New file'); // A Rejbrand Text Editor window
  HIco := SendMessage(HWin, WM_GETICON, ICON_BIG, 0);
  if HIco = 0 then
    HIco := SendMessage(HWin, WM_GETICON, ICON_SMALL2, 0);
  Self.Icon.ReleaseHandle; // important!
  Self.Icon.Handle := HIco;
end;

Upvotes: 4

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