Question

我有一个控件（DateRangeSelector），它根据下面的代码注册依赖属性及其回调（TodayDateChanged）：

DateRangeSelector.cs：

public static readonly DependencyProperty TodayDateProperty =
DependencyProperty.Register("TodayDate", typeof(bool),
                            typeof(DateRangeSelectorControl),
                            new PropertyMetadata(true, TodayDateChanged));

private static void TodayDateChanged(DependencyObject d,
DependencyPropertyChangedEventArgs e) {
    ((DateRangeSelectorControl)d).TodayDateChanged(); 
}

public bool TodayDate { 
    get { return (bool)GetValue(TodayDateProperty); }
    set { SetValue(TodayDateProperty, value); } 
}

此控件正在另一个XAML（ActivityListMenuControlView.xaml）中用作：

<DateRangeSelector:DateRangeSelectorControl x:Name="DateRangeSelector"
                                            Grid.Column="1"
                                            Margin="10 0 0 0"
                                            HorizontalAlignment="Left"
                                            VerticalAlignment="Center"
                                            AutomationProperties.AutomationId="AID_TaskListDateRangeSelector"
                                            DateRangeUpdatedCmd="{Binding Path=DateRangeSelectionUpdatedCommand}"
                                            FontSize="{StaticResource TaskListMenuFontSize}"
                                            RangeOptions="{Binding Path=DateRangeSelectionOptions,
                                                                   Mode=OneTime}"
                                            SelectedDateRange="{Binding Path=SelectedRange,
                                                                        Mode=TwoWay}"
                                            Visibility="{Binding Path=ShowFilterOptions,
                                                                 Converter={StaticResource boolToVisibility}}"
                                            TodayDate="{Binding TodayDate, ElementName=DateRangeSelector}" />

请注意，DateRangeSelector的依赖项属性包装器“TodayDate”绑定到视图模型（ActivityListMenuControlViewModel）中名为“TodayDate”的另一个属性并通过其显示。这是视图模型代码：

private bool m_UpdateTodayDate; 
public bool TodayDate
{
    get { return m_UpdateTodayDate; }
    set 
    {
        m_UpdateTodayDate = value;
        OnPropertyChanged("TodayDate");
    } 
}

现在终于在另一个视图模型中，每次为此属性分配相同的值： ActivityListContainerViewModel.cs：

private void RefreshModule(bool updateDateRangeSelectorCtrl)
{
    //"Today" filter date changed: Update DateRangeSelector
    if (updateDateRangeSelectorCtrl)
    {
        m_MenuControlViewModel.TodayDate = true;
    }
}

问题：DateRangeSelector中的属性更改回调“TodayDateChanged”从未被触发过。我调试了代码，但控件从未点击此回调。

我在代码中做错了吗？

更新：根据“franssu”的评论我改变了我的绑定如下：

<DateRangeSelector:DateRangeSelectorControl x:Name="DateRangeSelector" DataContext="MenuControlViewModel"                                     TodayDate="{Binding TodayDate,Mode=TwoWay}"                            />

仍然没有运气！没有回调。

Answer 1

<DateRangeSelector:DateRangeSelectorControl x:Name="DateRangeSelector"
[...]
TodayDate="{Binding TodayDate, ElementName=DateRangeSelector}" />

您将属性绑定到自身，即控件的属性，而不是VM的属性。

依赖属性更改了回调未触发

1 个答案: