private void MonthView_OnDayDoubleClicked(object sender, CalendarDay e)
{
var calendar = (MonthView)sender;
Debug.WriteLine("double clicked: {0:d}", (object)e.Date);
var eventText = InputTextBox.Show("Bezeichnung:");
if (!string.IsNullOrEmpty(eventText))
{
var appointment = new CalendarAppointment(e.Date, eventText);
this.Appointments.Add(appointment);
}
}