procedure Klass_Name(const tl: TCustommemo); 
var h: THandle; 
  buf: array[0..1, 0..99] of char; 
  sl: Tstringlist; 
begin 
  sl := Tstringlist.create; 
  sl.sorted := true; 
  sl.Duplicates := dupIgnore; 
  h := findwindow(nil, nil); 
  while h > 0 do begin 
    if iswindowvisible(h) then begin 
      getclassname(h, buf[0], 100); 
      GetWindowText(h, buf[1], 100); 
      if string(buf[1]) <> '' then 
        sl.add(buf[1] + '------->' + buf[0]); 
    end; 
    h := getnextwindow(h, GW_HWNDNEXT); 
  end; 
  tl.lines := sl; 
  sl.free; 
end; 
 
// Beispielaufruf 
procedure TForm1.Button9Click(Sender: TObject); 
begin 
  Klass_Name(Memo1); 
end;