1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:

function EnumProc(wnd: HWND; Lines: TStrings): BOOL; stdcall;
var
  buf, Caption: array[0..255] of char;
begin
  Result := True;
  GetClassName(wnd, buf, SizeOf(buf) - 1);
  SendMessage(wnd, WM_GETTEXT, 256, Integer(@Caption));
  Lines.Add(Format('ID: %d, ClassName: %s, Caption: %s',
           [GetDlgCtrlID(wnd), buf, Caption]));
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
 ListBox1.Clear; EnumChildWindows(Application.Handle, @EnumProc, Integer(ListBox2.Items));
end;                    

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:

function EnumerateThreadWindows(Wnd: HWND; Data: lParam): BOOL;
var
  WindowText: array[0..255] of char; // holds the text of the window
  WindowText1: PChar;
begin
  { Get the text from the window }
  GetWindowText(Wnd, WindowText, 255);
  { Display it in the listbox}
  //ShowMessage(WindowText);
  Form1.ListBox1.Items.Add(WindowText);
  { Continue the enumeration }
  Result := True;
end;

procedure TRetForm.Button1Click(Sender: TObject);
begin
EnumThreadWindows(GetCurrentThreadID, @EnumerateThreadWindows, 0);
end;                    

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:

function EnumerateThreadWindows(Wnd: HWND; Data: lParam): BOOL;stdcall;
var
  WindowText: string;
  pid: integer;
begin
  GetWindowThreadProcessID(Wnd,@pid);
  if IsWindowVisible(Wnd) and (pid = Data) then
    begin
      SetLength(WindowText,MAX_PATH);
      GetWindowText(Wnd, @WindowText[1], MAX_PATH - 1);
      SetLength(WindowText,StrLen(PChar(WindowText)));
      Form1.ListBox1.Items.Add(WindowText);
    end;
  Result := True;
end;


procedure TForm1.Button1Click(Sender: TObject);
var pid: integer;
begin
  GetWindowThreadProcessID(Handle,@pid);
  EnumWindows(@EnumerateThreadWindows, pid);
end;                    

1:

GetWindowThreadProcessID(Wnd,@pid);                    

1:

Windows.GetWindowThreadProcessID(Wnd,@pid);                    

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:

procedure ListOwnForms(const sl: TStrings; OnlyVisible: Boolean = True);
var i: Integer;
begin
  sl.BeginUpdate;
  try
    for i := 0 to Screen.FormCount - 1 do
      if Screen.Forms[i].Showing or not OnlyVisible then
        sl.Add(Screen.Forms[i].Caption);
  finally
    sl.EndUpdate;
  end;
end;