Xceed.Wpf.Toolkit.DateTimePicker.OnIsOpenChanged C# (CSharp) Method

    protected override void OnIsOpenChanged( bool oldValue, bool newValue )
    {
      base.OnIsOpenChanged( oldValue, newValue );

      if( !newValue )
      {
        _calendarTemporaryDateTime = null;
        _calendarIntendedDateTime = null;
      }
    }

        private static void OnIsOpenChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            DateTimePicker dateTimePicker = ( DateTimePicker )d;

            if (dateTimePicker != null)
            {
                dateTimePicker.OnIsOpenChanged(( bool )e.OldValue, ( bool )e.NewValue);
            }
        }