private void MonthCalendar1OnDragEnterDate(object sender, DragDateEventArgs e)
 {
     Debug.WriteLine($"DragEnterDate {e.Time}");
 }
 protected virtual void OnDragEnterDate(DragDateEventArgs e)
 {
     DragEnterDate?.Invoke(this, e);
 }
 private void MonthCalendar1OnDragLeaveDate(object sender, DragDateEventArgs e)
 {
     e.Effect = DragDropEffects.None;
 }