如何在 UWP MVVM 中使用 CalenderView [英] How to use CalenderView in UWP MVVM

问题描述

我想绑定选定的日历视图项并将其设置为一个日期时间变量.

I want to bind the selected Calender View Item and set it to a DateTime Variable.

我的 CalenderView Xaml 看起来像:

My CalenderView Xaml looks like:

<CalendarView Grid.Row="6"  Grid.ColumnSpan="2"  VerticalAlignment="Center" HorizontalAlignment="Center" FontSize="20"/>

我在 Datacontext 类中有一个 DateTime 项目:

I have an DateTime item in the Datacontext class:

    private DateTime _DueDate;
    public DateTime DueDate
    {
        get { return this._DueDate; }
        set
        {
            if (this._DueDate != value)
            {
                this._DueDate = value;
                base.PropertyOnChanged("DueDate");
            }
        }
    } 

和 DateTimeConverter:

And the DateTimeConverter:

    public class DateConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, string language)
    {
        DateTime date = ((DateTime)value);
        return date.Day + "." + date.Month + "." + date.Year;
    }

    public object ConvertBack(object value, Type targetType, object parameter, string language)
    {
        return DateTime.Parse((string)value);
    }
}

这也是日历视图的文档:

Here is also the Doc to the Calender View:

CalenderView MSDN

在文档中是一个属性 SelectedDate，但我只在 XAML SelectedDateChanged EventHandler 中看到.但我想在 MVVM 中做到这一点.

In the Docs is a Property SelectedDate, but I only see in the XAML SelectedDateChanged EventHandler. But I want to do it in MVVM.

我的问题是我不知道我可以在哪个属性上设置捆绑.我查看了文档，但只找到了 Date="" 属性来自 DatePicker，但我在 CalenderView 中找不到任何内容.

My Problem is I don´t know on which Property I can set the Binding. I looked in the Doc but I only find the Date="" property from the DatePicker but I don´t find anything to the CalenderView.

更新

关注来自

@Juo Zuo:"CalendarView 有一个 SelectedDates 属性.通常，我们可以使用这个属性来设置选定的日期，例如:MyCalendarView.SelectedDates.Add(new DateTime(2016, 5, 5));.但是这个属性是只读，我们不能用它来绑定.所以，恐怕没有办法用绑定设置选定的日期"

@Juo Zuo:"CalendarView has a SelectedDates property. Usually, we can use this property to set the selected date like: MyCalendarView.SelectedDates.Add(new DateTime(2016, 5, 5));. However this property is read-only, we can't use it for binding. So, I'm afraid there is no way to set selected dates with Binding"

我会扩展问题.

我的问题是:

有什么办法可以使用来自 MSDN 的 MVVM 模式的日历视图吗?

Is there any way to use the Calender View with the MVVM Pattern from MSDN ?

推荐答案

您需要做的就是创建一个附加属性并将SelectedDates.Add 逻辑封装在其中

All you need to do is to create an attached property and encapsulate the SelectedDates.Add logic within it.

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);
                    }
                }
            }));
}

<CalendarView local:CalendarViewHelper.SelectedDates="{x:Bind Dates, Mode=OneWay}" />

如果您的 Dates 属性包含多个项目，请确保将 SelectionMode 更改为 Multiple.

If your Dates property has more than one items inside, make sure you change the SelectionMode to Multiple.

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