UWP：在日历视图中绑定选定日期

Question

我想在我的 XAML 日历视图中进行从我的 ViewModel 到选定日期（单个）的双向绑定。但是我们没有依赖属性来做。

怎么办？

编辑：我试过的代码，但我得到了错误。它结合了这两个主题： How to select rang of dates on finger slide on Calendar Control - UWP Win10 VS2015 XAML:

<CalendarView  MinHeight="250" MaxHeight="500" MaxWidth="720"   FontWeight="Normal" 
             DayItemFontWeight="Light" MinWidth="100"
                          SelectionMode="Single"
                          Style="{StaticResource Mahcalenderstyle}" Visibility="Visible" 
             HorizontalAlignment="Stretch" x:Name="MyCalendarView" DisplayMode="Month" Margin="9,25,9,0"
             VerticalAlignment="Top" SelectedDatesChanged="CalendarView_SelectedDatesChanged"
             CalendarViewDayItemStyle="{StaticResource CalendarViewDayItemStyle1}"
                          />

我的虚拟机：

 private DateTimeOffset _selecteddate;
    public DateTimeOffset SelectedDate
    {
        get
        {
            return _selecteddate;

        }
        set
        {

            if (_selecteddate != value)
            {
                _selecteddate = value;
                if (PropertyChanged != null)
                {
                    PropertyChanged(this,
                        new PropertyChangedEventArgs("SelectedDate"));
                }
            }
        }
    }
    public CalendarViewModel()
    {

        SelectedDate = DateTimeOffset.Now;}

帮手：

 public static class CalendarViewHelper
{
    public static IList<DateTimeOffset> GetSelectedDates(DependencyObject obj)
    {
        return (IList<DateTimeOffset>)obj.GetValue(SelectedDatesProperty);
    }

    public static void SetSelectedDates(DependencyObject obj, IList<DateTimeOffset> value)
    {
        obj.SetValue(SelectedDatesProperty, value);
    }

    public static readonly DependencyProperty SelectedDatesProperty =
        DependencyProperty.RegisterAttached("SelectedDates", typeof(IList<DateTimeOffset>), typeof(CalendarView),
            new PropertyMetadata(null, (d, e) =>
            {
                var cv = d as CalendarView;
                var dates = e.NewValue as IList<DateTimeOffset>;

                if (cv != null && dates != null)
                {
                    foreach (var date in dates)
                    {
                        cv.SelectedDates.Add(date);
                    }
                }
            }));

}

Answer 1

您需要创建 DateTimeOffset 的附加属性，而不是 IList<DateTimeOffset>，因为您只想 select 一个日期。

因此，您需要这样的东西，而不是您从我的其他答案复制过来的代码 -

public static class CalendarViewHelper
{
    public static DateTimeOffset GetSelectedDate(DependencyObject obj)
    {
        return (DateTimeOffset)obj.GetValue(SelectedDateProperty);
    }

    public static void SetSelectedDate(DependencyObject obj, DateTimeOffset value)
    {
        obj.SetValue(SelectedDateProperty, value);
    }

    public static readonly DependencyProperty SelectedDateProperty =
        DependencyProperty.RegisterAttached("SelectedDate", typeof(DateTimeOffset), typeof(CalendarView),
            new PropertyMetadata(null, (d, e) =>
            {
                var cv = (CalendarView)d;
                var date = (DateTimeOffset)e.NewValue;

                cv.SelectedDates.Clear();
                cv.SelectedDates.Add(date);
            }));
}

请注意，您需要调用 Clear 来清除所有之前 selected 的日期，因为 SelectionMode 设置为 Single，而不是这样做, 将抛出错误。

然后您只需要将它连接到 xaml 和您的 SelectedDate 属性。

<CalendarView SelectionMode="Single"
                  DisplayMode="Month"
                  local:CalendarViewHelper.SelectedDate="{x:Bind SelectedDate, Mode=OneWay}" />

UWP：在日历视图中绑定选定日期

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