private void button1_Click(object sender, EventArgs e) { string startDate = this.monthCalendar1.SelectionRange.Start.ToShortDateString(); string endDate = this.monthCalendar2.SelectionRange.Start.ToShortDateString(); int startDateDay = int.Parse(startDate[0].ToString() + startDate[1].ToString()); int startDateMonth = int.Parse(startDate[3].ToString() + startDate[4].ToString()); int startDateYear = int.Parse(startDate[6].ToString() + startDate[7].ToString() + startDate[8].ToString() + startDate[9].ToString()); int endDateDay = int.Parse(endDate[0].ToString() + endDate[1].ToString()); int endDateMonth = int.Parse(endDate[3].ToString() + endDate[4].ToString()); int endDateYear = int.Parse(endDate[6].ToString() + endDate[7].ToString() + endDate[8].ToString() + endDate[9].ToString()); DateTime date1 = new DateTime(startDateYear, startDateMonth, startDateDay); DateTime date2 = new DateTime(endDateYear, endDateMonth, endDateDay); try { Age cDate = new Age(date1); Age diff = cDate.Count(date1, date2); label6.Text = diff.Years.ToString(); label7.Text = diff.Months.ToString(); label8.Text = diff.Days.ToString(); } catch (ArgumentException error) { MessageBox.Show(error.Message, "Warning Message!"); } }