private void CalendarSelectedDatesChanged(object sender, SelectionChangedEventArgs e)
{
_popup.IsOpen = false;
_datePickerTextBox.Text = _calendar.SelectedDate.ToString();
_datePickerTextBox.Focus();
_datePickerTextBox.Select(0, 4);
}
private void Dp_geburtsdatum_Loaded(object sender, RoutedEventArgs e)
{
DatePickerTextBox datePickerTextBox = (DatePickerTextBox)dp_geburtsdatum.Template.FindName("PART_TextBox", dp_geburtsdatum);
if (datePickerTextBox != null)
{
datePickerTextBox.Focus();
}
}