MouseEvent没有冒泡

Question

我有两个相交的矩形。当鼠标悬停在它们上面时，我想改变两者的不透明度。当鼠标放在其中一个上时，它就会工作。但是，当鼠标位于矩形的相交区域时，只有上面的矩形改变其不透明度。你能告诉我在这种情况下我怎样才能让这两个矩形改变不透明度吗?

<Window x:Class="WpfTestApp.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:WpfTestApp="clr-namespace:WpfTestApp" Title="MainWindow" Height="350" Width="525" >
<Window.Resources>
    <Style x:Key="RectangleHighlighter" TargetType="{x:Type Rectangle}">
        <Setter Property="Opacity" Value="0.25" />
        <Style.Triggers>
            <Trigger Property="IsMouseOver" Value="True">
                <Setter Property="Opacity" Value="1" />
            </Trigger>
        </Style.Triggers>
    </Style>
</Window.Resources>
    <Grid x:Name="LayoutRoot">
        <Rectangle Stroke="Black" Width="100" Fill="Green" Height="1000" Margin="0,15,0,0" Style="{StaticResource RectangleHighlighter}"/>
        <Rectangle Stroke="Black" Width="1000" Fill="Green" Height="100" Margin="0,15,0,0" Style="{StaticResource RectangleHighlighter}"/>
    </Grid>
</Window>

Answer 1

实际上与HiTech Magic描述的方法相似:

<Window.Resources>
    <Style x:Key="RectangleHighlighter" TargetType="{x:Type Rectangle}">
        <Setter Property="Opacity" Value="0.25" />
        <Style.Triggers>
            <Trigger Property="Tag" Value="MouseOver">
                <Setter Property="Opacity" Value="1" />
            </Trigger>
        </Style.Triggers>
    </Style>
</Window.Resources>
<Grid x:Name="LayoutRoot" Background="Transparent" MouseMove="LayoutRoot_MouseMove">
    <Rectangle Stroke="Black" Width="100" Fill="Green" Height="1000" Margin="0,15,0,0" Style="{StaticResource RectangleHighlighter}"/>
    <Rectangle Stroke="Black" Width="1000" Fill="Green" Height="100" Margin="0,15,0,0" Style="{StaticResource RectangleHighlighter}"/>
</Grid>

及其背后的代码:

    private List<DependencyObject> hitResultsList = new List<DependencyObject>();
    private void LayoutRoot_MouseMove(object sender, MouseEventArgs e)
    {
        // Retrieve the coordinate of the mouse position.
        Point pt = e.GetPosition((UIElement)sender);
        // Clear the contents of the list used for hit test results.
        hitResultsList.Clear();
        // Set up a callback to receive the hit test result enumeration.
        VisualTreeHelper.HitTest(LayoutRoot, null,
            new HitTestResultCallback(MyHitTestResult),
            new PointHitTestParameters(pt));
        // Unset all children
        for (int i = 0; i < VisualTreeHelper.GetChildrenCount(LayoutRoot); ++i)
        {
            var element = VisualTreeHelper.GetChild(LayoutRoot, i) as FrameworkElement;
            if (element != null)
            {
                element.Tag = null;
            }
        }
        // Perform actions on the hit test results list.
        foreach (var dependencyObject in hitResultsList)
        {
            var element = dependencyObject as FrameworkElement;
            if (element != null)
            {
                element.Tag = "MouseOver";
            }
        }
    }
    // Return the result of the hit test to the callback.
    public HitTestResultBehavior MyHitTestResult(HitTestResult result)
    {
        // Add the hit test result to the list that will be processed after the enumeration.
        hitResultsList.Add(result.VisualHit);
        // Set the behavior to return visuals at all z-order levels.
        return HitTestResultBehavior.Continue;
    }

当然，在这种情况下，最好添加一些特殊的附加属性和行为

Answer 2

您需要将悬停处理程序添加到父网格中，使两个矩形都具有IsHitTestVisible=False并使用VisualTreeHelper。FindElementsInHostCoordinates来确定实际在鼠标下面的对象(1个或更多)。

如果你必须让它基于样式，马里奥·维尔纳里的建议将工作，但悬停将触发在网格的任何地方，而不仅仅是在矩形。

这对我来说是一个非常有用的附加行为的想法。这种行为将实现上面列出的代码，但会触发子对象上的悬停事件，所以你仍然可以使用样式来实现……我得试试

Answer 3

尝试将样式应用到Grid元素