Delphi inspect external TLabels inside a TGroupBox via EnumWindows, Enumchildwindows or Spy++

Question

I am developing an application in Delphi XE2 which inspects, through the functions EnumWindows and EnumChildWindows a window of a running application also written in Delphi.

This is the main code (adapted from an example: http://www.swissdelphicenter.ch/torry/showcode.php?id=410)

function EnumChildWindowsProc(Wnd: HWnd; Form: TForm1): Bool; export;
  {$ifdef Win32} stdcall; {$endif}
var
  Buffer: array[0..99] of Char;
begin
  GetWindowText(Wnd, Buffer, 100);

  if StrPas(Buffer) = '' then Buffer := 'Empty';
  new(AWindows);
  with AWindows^ do
  begin
    WindowHandle := Wnd;
    WindowText   := StrPas(Buffer);
  end;

  CNode := Form1.TreeView1.Items.AddChildObject(PNode,
               AWindows^.WindowText + ':' +
               IntToHex(AWindows^.WindowHandle, 8), AWindows);

  if GetWindow(Wnd, GW_CHILD) = 0 then
  begin
    PNode := CNode;
    Enumchildwindows(Wnd, @EnumChildWindowsProc, 0);
  end;
  Result := True;
end;

function EnumWindowsProc(Wnd: HWnd; Form: TForm1): Bool;
  export; {$ifdef Win32} stdcall; {$endif}
var
  Buffer: array[0..99] of Char;
begin
  GetWindowText(Wnd, Buffer, 100);

  if StrPas(Buffer) = '' then Buffer := 'Empty';
  new(AWindows);
  with AWindows^ do
  begin
    WindowHandle := Wnd;
    WindowText   := StrPas(Buffer);
  end;

  if Pos(Form1.edAppToFind.Text,AWindows^.WindowText) > 0 then // <- inspect child only for my Application
  begin
    PNode := Form1.TreeView1.Items.AddObject(nil, AWindows^.WindowText + ':' +
      IntToHex(AWindows^.WindowHandle, 8), AWindows);
    EnumChildWindows(Wnd, @EnumChildWindowsProc, 0);
  end;
  Result := True;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  EnumWindows(@EnumWindowsProc, self.Handle);
end;

Everything works well, except for the object TGroupBox after which the recursion stops. But control TGroupBox contains inside other elements (TLabel).

In fact, even writing a simple application in Delphi, by including in the Form a TGroupBox and then into the TGroupBox a TLabel, launching the Application and inspecting it with Spy++ (or with the Tool Autoit AU3Info) you can not enter into the TGroupBox: the TLabel inside is not inspected.

Is there a way to find TLabel control within the TGroupBox?

Answer 1

This is not an issue with the group box control. The issue is that the TLabel control is not windowed. There's no window handle associated with it and so it cannot be found by Spy++, EnumChildWindows etc.