如何让网格捕获鼠标，但仍允许其子级处理点击事件

Question

如果标题令人困惑，请提前道歉。这是情况。我有一个名为grdFilters 的网格。该网格中有一系列CheckBoxes（每行一个）。通常这个网格是隐藏的。但我希望它在提示时显示（在按钮单击时），并在用户单击网格以外的某个位置时离开。为了处理外部控制鼠标点击，我首先尝试捕获鼠标：

    AddHandler(Mouse.PreviewMouseDownOutsideCapturedElementEvent, new MouseButtonEventHandler(HandleClickOutsideOfControl));

    private void HandleClickOutsideOfControl(object sender, MouseButtonEventArgs e)
    {
        if (this.filters) //Check if the Filters grid is visible
        {
            ShowHideMenu("sbHideFilters", grdFilters); //Method that hides the grid
            Mouse.Capture(null); //Release the mouse
        }
    }

    private void btnFilters_Click(object sender, RoutedEventArgs e)
    {
        if (!this.filters) //Check if the filters grid is shown
        {
            ShowHideMenu("sbShowFilters", grdFilters); //Method that reveals the grid
            Mouse.Capture(grdFilters); //Capture the mouse
        }
    }

问题是，当过滤器网格捕获了鼠标时，没有一个子网格（复选框）可以被点击。我真的很想找到一种方法来检测何时在网格外单击鼠标，同时仍允许网格的子级接受鼠标按下事件。任何帮助将不胜感激，在此先感谢。

根据要求，这里是我的一些 Xaml：

<Grid>
    <Label x:Name="label" Content="Events" HorizontalAlignment="Center" VerticalAlignment="Top"/>
    <ScrollViewer HorizontalAlignment="Left" Height="619" Margin="0,26,0,0" VerticalAlignment="Top" Width="450" VerticalScrollBarVisibility="Hidden">
        <Grid x:Name="Schedule" HorizontalAlignment="Left" Height="Auto" VerticalAlignment="Top" Width="450" Margin="10,0,0,0"/>
    </ScrollViewer>
    <Grid x:Name="grdFilters" HorizontalAlignment="Left" Height="619" Margin="490,26,-176,0" VerticalAlignment="Top" Width="135" Background="{StaticResource TransparentBackground}" Panel.ZIndex="95">
        <CheckBox x:Name="chckAll" Content="All" HorizontalAlignment="Left" Margin="0,10,0,0" VerticalAlignment="Top" Checked="chckAll_Checked" Unchecked="chckAll_Unchecked"/>
        <Grid x:Name="grdFilters" HorizontalAlignment="Left" Height="588" Margin="0,31,0,0" VerticalAlignment="Top" Width="136"/>
    </Grid>
    <Button x:Name="btnFilters" Content="" Margin="436,223,-18,0" VerticalAlignment="Top" Background="Cyan" Opacity="0.15" Style="{StaticResource MyTabStyle}" Height="80" Click="btnFilters_Click"/>

</Grid>

我唯一遗漏的是资源字典和页面定义本身。

Answer 1

我认为Mouse.Capture 和PreviewMouseDownOutsideCapturedElementEvent 过于具体，无法满足您的需求。

我宁愿使用hitResultsList，它可以用于很多不同的场景：

我稍微修改了一下诶AddHandler

AddHandler(Mouse.PreviewMouseDownEvent, new MouseButtonEventHandler(HandleMouseDown));

我添加了VisualTreeHelper.HitTest 逻辑

    //List to store all the elements under the cursor
    private List<DependencyObject> hitResultsList = new List<DependencyObject>();

    private void HandleMouseDown(object sender, MouseButtonEventArgs e)
    {

        Point pt = e.GetPosition((UIElement)sender);
        hitResultsList.Clear();

        //Retrieving all the elements under the cursor
        VisualTreeHelper.HitTest(this, null,
            new HitTestResultCallback(MyHitTestResult),
            new PointHitTestParameters(pt));

        //Testing if the grdFilters is under the cursor
        if (!hitResultsList.Contains(this.grdFilters) && grdFilters.Visibility == System.Windows.Visibility.Visible)
        {
            grdFilters.Visibility = System.Windows.Visibility.Hidden;
        }
    }

    //Necessary callback function
    private HitTestResultBehavior MyHitTestResult(HitTestResult result)
    {
        hitResultsList.Add(result.VisualHit);
        return HitTestResultBehavior.Continue;
    }

这样您还可以从 btnFilters_Click 中删除 Mouse.Capture 调用：

    private void btnFilters_Click(object sender, RoutedEventArgs e)
    {
        if (grdFilters.Visibility != System.Windows.Visibility.Visible)
            grdFilters.Visibility = System.Windows.Visibility.Visible; }
    }