uses DateUtils;

procedure TForm1.MonthCalendar1Click(Sender: TObject);

begin

caption:= YearOf(MonthCalendar1.Date).ToString + '-' + MonthOfTheYear(MonthCalendar1.Date).ToString + '-' + DayOfTheMonth(MonthCalendar1.Date).ToString;

//caption:=DateTimeToStr(MonthCalendar1.Date);

end;