DELPHI - FAQ

function Frage(const s: string; Default_NO: Boolean = False): boolean;
begin
  if Default_NO then
    with CreateMessageDialog(s, mtConfirmation, [mbYes, mbNo]) do
    try
      ActiveControl := FindComponent('NO') as TWinControl;
      Result := ShowModal = mrYes;
    finally
      Free;
    end
  else
    Result := MessageDlg(s, mtConfirmation, [mbYes, mbNo], 0) = mrYes;
end;