Calendar Schedule in C# Windows Application

http://stackoverflow.com/questions/1738824/c-sharp-and-month-calendar-selecting-multiple-dates

In the above link, he used following code in the KeyPress event handler

            MonthCalendar.HitTestInfo info = monthCalendar1.HitTest(e.Location);
            if (info.HitArea == MonthCalendar.HitArea.Date)
            {
                if (monthCalendar1.BoldedDates.Contains(info.Time))
                {
                    monthCalendar1.RemoveBoldedDate(info.Time);
                }
                else
                {
                    monthCalendar1.AddBoldedDate(info.Time);
                    monthCalendar1.UpdateBoldedDates();
                }
            }

Hope it will help