TCalendarDialog/zh CN

procedure TForm1.Button1Click(Sender: TObject);
var
    dt:tdatetime;
    calendarSettings:TDisplaySettings;
begin
  dt:= now;
  CalendarDialog1.Date := dt;
  calendarSettings:= [dsShowWeekNumbers,dsStartMonday];
  CalendarDialog1.Title:='Select a date';
  CalendarDialog1.DisplaySettings:= calendarSettings;
  if CalendarDialog1.Execute then
    begin
      dt:= CalendarDialog1.Date;
      ShowMessage( 'The selected date is '+FormatDateTime( 'yyyy-mm-dd',dt ));
    end
  else
    ShowMessage( 'Today is '+FormatDateTime( 'yyyy-mm-dd',dt ));
end;