Listing all open windows

To list (get) all open windows, you must use EnumWindows API function. It uses a callback function, that receives 2 parameters: a Window handle and a Pointer.
You can use it with a code like this (this code lists all open windows, even invisible ones in a listbox):

function EnumWindowsProc(Wnd : HWnd;Form : TForm1) : Boolean; Export;
{$ifdef Win32} StdCall; {$endif}

var

  Buffer : Array[0..99] of char;

begin

  GetWindowText(Wnd,Buffer,100);

  if StrLen(Buffer) <> 0 then

    Form.ListBox1.Items.Add(StrPas(Buffer));

  Result := True;

end;



procedure TForm1.Button1Click(Sender: TObject);

begin

  EnumWindows(@EnumWindowsProc,LongInt(Self));

end;