Procedure TForm1.Button1Click(Sender: TObject);
type
  PForm = ^TForm;
  PClass = ^TClass;
var
  formPtr : PForm;
  I: Integer;
  msg : string;
  windowHandle : HWND;
begin
  windowHandle := FindWindow('TForm1', 'FORMSSSSS');
  formPtr := PForm(GetVCLObjectAddr(windowHandle) + 4);
  if (not Assigned(formPtr)) then Exit;
  for I := 0 to formPtr^.ControlCount - 1 do // Error
  begin
    msg := msg + formPtr^.Controls[i].Name;
    if formPtr^.Controls[i].Name = 'StringGrid1' then
    begin
      msg := TStringGrid(formPtr^.Controls[i]).Cells[1, 1];
    end;

  end;
  ShowMessage(msg);
end;


function GetVCLObjectAddr(AHandle: HWND): DWORD;
var
  pid: DWORD;
begin
  pid := 0;
  GetWindowThreadProcessId(AHandle, pid);
  if (pid =0) then
  begin
    Result := 0;
    Exit;
  end;
  Result := GetPropW(AHandle, PWideChar(WideString(Format('Delphi%.8X', [PID]))))
end;

Procedure TForm1.Button1Click(Sender: TObject);
var
  formPtr : TForm;
  I: Integer;
  msg : string;
  windowHandle : HWND;
begin
  windowHandle := FindWindow('TForm1', 'FORMSSSSS');
  formPtr := TForm(GetVCLObjectAddr(windowHandle) + 4);
  if (not Assigned(formPtr)) then Exit;
  for I := 0 to formPtr.ControlCount - 1 do
  begin
    msg := msg + formPtr.Controls[i].Name;
    if formPtr.Controls[i].Name = 'StringGrid1' then
    begin
      msg := TStringGrid(formPtr.Controls[i]).Cells[1, 1];
    end;
  end;
  ShowMessage(msg);
end;