WPF-MVVM将ViewModel-Property绑定到嵌套的UserControl

Question

正如标题所说,我想将一个属性从我的ViewModel绑定到相应视图中的嵌套UserControl.我不能按照我需要的方式工作.

嵌套的UserControl只不过是DatePicker一个DropDown小时和一个小时.如何告诉DatePicker我们选择ViewModel传播的日期作为其选定日期？

我几乎尝试了一切,现在我离窗户不远了.如你所见,任何帮助表示赞赏;)

现在到目前为止的代码:DateTimePicker.xaml.cs(CodeBehind)

public partial class DateTimePicker
{
    public static DependencyProperty SelectedDateValueProperty = DependencyProperty.Register("SelectedDateValue", typeof (DateTime), typeof (DateTimePicker), new FrameworkPropertyMetadata(default(DateTime), FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, OnPropertyChangedCallback));

    private static void OnPropertyChangedCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs args)
    {
        Debug.WriteLine("Wohoo. I'm here and still debugging...");
    }

    public DateTimePicker()
    {
        InitializeComponent();

        DataContext = this;

        var times = GetTimes();

        Times.ItemsSource = times;
        Times.SelectedItem = times.First();
    }

    public DateTime SelectedDateValue
    {
        get { return (DateTime) GetValue(SelectedDateValueProperty); }
        set { SetValue(SelectedDateValueProperty, value); }
    }
}

嵌套的UserControl(DateTimePicker.xaml):

<UserControl x:Class="Framework.Controls.DateTimePicker"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
         mc:Ignorable="d" 
         d:DesignHeight="30" d:DesignWidth="200"
         DataContext="{Binding RelativeSource={RelativeSource Self}}">
<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="3*" />
        <ColumnDefinition Width="2*" />
    </Grid.ColumnDefinitions>
    <DatePicker HorizontalAlignment="Left" Name="DatePickerCalendar" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Center" SelectedDate="{Binding SelectedDateValue}" />
    <ComboBox Grid.Column="1" VerticalAlignment="Center" Name="Times" DisplayMemberPath="Name" />
</Grid>

并且,最后但并非最不重要:具有嵌套UserControl的View(View.xaml)

<CustomControls:DateTimePicker SelectedDateValue="{Binding LocalRegistrationStartDate, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

希望问题很清楚,任何人都可以帮助我,或者说明我在这里做错了什么.

Answer 1

使用:

"{Binding SelectedDateValue}"

告诉WPF"嘿,检查我DataContext的财产SelectedDateValue".

你想要的是Property从你的用户控制中获取.

最简单的方法是为您的用户控制一个名称,如:

<UserControl x:Name="myControl"/>

然后将绑定修改为:

"{Binding ElementName=myControl, Path=SelectedDateValue}"