Question

我在UserControl中有一个TreeView，它可以滚动+缩放和拖动。（因为TreeView非常庞大）因为Scroll / Zoom / Drag UserControl正在监听

OnScrollViewerScrollChanged
OnMouseLeftButtonUp
OnMouseLeftButtonUp
OnPreviewMouseWheel
OnMouseLeftButtonDown
的OnMouseMove

TreeViewItems无法接收任何鼠标输入。因此，我为TreeViewItem创建了一个DependencyProperty，所谓的IsMouseHover。如果鼠标进入或离开TreeViewItem，则DP在true和false之间切换。

ScrollZoomDrag UserControl还有一个DP，所谓的“Active”，它订阅或取消订阅上面提到的所有事件。

现在我想将TreeViewItem的“IsMouseHover”绑定到ScrollZoomDrag的Control“Active”DP。

    <controls:ScrollDragZoomControl>
    <controls:OrgTreeView ItemsSource="{Binding Root}">
        <controls:OrgTreeView.ItemTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding Children, Mode=TwoWay}">
                <controls:VisualElement DataContext="{Binding}">
                    <Style TargetType="controls:ScrollDragZoomControl">
                        <Style.Triggers>
                            <DataTrigger Binding="{Binding RelativeSource={RelativeSource AncestorType=controls:VisualElement}, Path=IsMouseHover}" Value="True">
                                <Setter Property="Active" Value="False" />
                            </DataTrigger>
                            <DataTrigger Binding="{Binding RelativeSource={RelativeSource AncestorType=controls:VisualElement}, Path=IsMouseHover}" Value="False">
                                <Setter Property="Active" Value="True" />
                            </DataTrigger>
                        </Style.Triggers>
                    </Style>
                </controls:VisualElement>
            </HierarchicalDataTemplate>
        </controls:OrgTreeView.ItemTemplate>
    </controls:OrgTreeView>
</controls:ScrollDragZoomControl>

使用上面的解决方案，ScrollZoomDrag的DP“Active”根本不会切换。我错过了什么或者有更好的方法吗？

更新

ScrollZoomDrag.xaml.cs

        public static readonly DependencyProperty ActiveProperty = DependencyProperty.Register("Active", typeof(bool), typeof(ScrollDragZoomControl), new PropertyMetadata(true, new PropertyChangedCallback(ActiveChanged)));

    public bool Active
    {
        get { return (bool)GetValue(ActiveProperty); }
        set { SetValue(ActiveProperty, value); }
    }

    public static void ActiveChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args)
    {
        ScrollDragZoomControl scrollDragZoomControl = (ScrollDragZoomControl)obj;

        if ((bool)args.NewValue)
            scrollDragZoomControl.StartListen();
        else scrollDragZoomControl.StopListen();
    }

VisualElement.xaml.cs

        public static readonly DependencyProperty IsMouseHoverProperty = DependencyProperty.Register("IsMouseHover", typeof(bool), typeof(VisualElement), new PropertyMetadata(false));

    public VisualElement()
    {
        InitializeComponent();
        MouseEnter += VisualElement_MouseEnter;
        MouseLeave += VisualElement_MouseLeave;
    }

    public bool IsMouseHover
    {
        get { return (bool)GetValue(IsMouseHoverProperty); }
        set { SetValue(IsMouseHoverProperty, value); }
    }

    private void VisualElement_MouseLeave(object sender, MouseEventArgs e)
    {
        IsMouseHover = false;
    }

    private void VisualElement_MouseEnter(object sender, MouseEventArgs e)
    {
        IsMouseHover = true;
    }

方法2 :(也不起作用）

    <controls:ScrollDragZoomControl>
    <controls:ScrollDragZoomControl.Style>
        <Style TargetType="controls:ScrollDragZoomControl">
            <Style.Triggers>
                <DataTrigger Binding="{Binding RelativeSource={RelativeSource AncestorType=controls:VisualElement}, Path=IsMouseHover}" Value="True">
                    <Setter Property="Active" Value="False" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </controls:ScrollDragZoomControl.Style>
    <controls:OrgTreeView ItemsSource="{Binding Root}"
                          HorizontalAlignment="Center"
                          VerticalAlignment="Center">
        <controls:OrgTreeView.ItemTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding Children, Mode=TwoWay}">
                <controls:VisualElement DataContext="{Binding}">                   
                </controls:VisualElement>
            </HierarchicalDataTemplate>
        </controls:OrgTreeView.ItemTemplate>
    </controls:OrgTreeView>
</controls:ScrollDragZoomControl>

Answer 1

尝试与Mode=OneWayToSource绑定：

IsMouseHover="{Binding RelativeSource={RelativeSource AncestorType=controls:ScrollDragZoomControl}, 
                       Path=Active, Mode=OneWayToSource}"

<controls:ScrollDragZoomControl>
  <controls:OrgTreeView ItemsSource="{Binding Root}">
    <controls:OrgTreeView.ItemTemplate>
       <HierarchicalDataTemplate ItemsSource="{Binding Children, Mode=TwoWay}">
         <controls:VisualElement DataContext="{Binding}" 
             IsMouseHover="{Binding RelativeSource={RelativeSource AncestorType=controls:ScrollDragZoomControl}, 
                                    Path=Active, Mode=OneWayToSource}">
         </controls:VisualElement>
      </HierarchicalDataTemplate>
    </controls:OrgTreeView.ItemTemplate>
  </controls:OrgTreeView>
</controls:ScrollDragZoomControl>

Answer 2

可能默认设置Active属性绑定TwoWay，以便它可以注册每个更改

new FrameworkPropertyMetadata(false, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));

我不确定，但是通知更改可能会有所帮助，或者您需要在xaml mode=TwoWay

中设置它

WPF将DependencyProperty绑定到另一个DependencyProperty

2 个答案: