C# InkCanvas子级的命中测试

我通过代码隐藏的方式在InkCanvas中添加了一个按钮。因为我不明白的原因

    HitTestResult result = VisualTreeHelper.HitTest(pe.InkCanvas.Children[2], point_MouseDown);

如果按钮的索引为2，则当我单击按钮时，结果始终为空

有人知道如何确定是否单击了子元素吗

任何帮助都将不胜感激。（是的，我在网上搜索没有成功。如果这是一个愚蠢的问题，我道歉）

系统：Windows 7、.net4.0 WPF C#

编辑：如果我在Children[0]是RichTextBox的情况下执行相同的操作，则上面的HitTest将重新返回非null。有人知道为什么吗

编辑：RichTextBox和按钮都添加到代码隐藏中，XAML是：

 <Grid Height="{x:Static local:pe.heightCanvas}" >

            <!--NotepadCanvas. Canvas used to place user writing lines and borders.-->
            <Canvas Name="NotePadCanvas" Panel.ZIndex="0"
                     Width="{x:Static local:pe.widthCanvas}" 
                     Height="{x:Static local:pe.heightCanvas}" 
                     Background="{Binding documenttype, Converter={StaticResource inkCanvasBackgroundConverter}}" />

            <!--BackgroundCanvas. Canvas used for special highlighting of seleted items-->
            <Canvas Name="BackgroundCanvas" Panel.ZIndex="1"
                     Width="{x:Static local:pe.widthCanvas}" 
                     Height="{x:Static local:pe.heightCanvas}" 
                     Background="Transparent" />

            <!--FormsCanvas. Canvas used to place formatted text from lists, etc.-->
            <Canvas Name="FormsCanvas" Panel.ZIndex="2"
                     Width="{x:Static local:pe.widthCanvas}" 
                     Height="{x:Static local:pe.heightCanvas}" 
                     Background="Transparent" />

            <!--TranscriptionCanvas. Canvas used to place recognized ink from the InkAnalyzer-->
            <Canvas Name="TranscriptionCanvas" Panel.ZIndex="3"
                     Width="{x:Static local:pe.widthCanvas}" 
                     Height="{x:Static local:pe.heightCanvas}" 
                     Background="Transparent" />

            <!--InkCanv. Top most canvas used to gather handwritten ink strokes from the user. EditingMode="Ink"   Gesture="OnGesture" -->
            <local:CustomInkCanvas x:Name="InkCanvas" Panel.ZIndex="4" 
                       Width="{x:Static local:pe.widthCanvas}"
                       Height ="{x:Static local:pe.heightCanvas}" 
                       Background="Transparent" 
                       AllowDrop="True"  Drop="InkCanvas_Drop"/>

        </Grid>

---

这是可行的，但它似乎很复杂，我不知道为什么按钮会显示为文本块：

...........

  Button btn = new Button();
        btn.Name = "Cancel";
        btn.Content = "Cancel";
        btn.Background = Brushes.Red;
        btn.Width = 50;
        btn.Height = 25;
        btn.RenderTransform = new System.Windows.Media.TranslateTransform(pe.InkCanvas.ActualWidth-btn.Width,topmargin);

        btnCancel = btn;
        pe.InkCanvas.Children.Add(btnCancel);

然后，在PreviewMouseLeftButtonDown（）中（代码在Microsoft网站上稍作修改）

// 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(pe.InkCanvas, null,
                    new HitTestResultCallback(MyHitTestResult),                        new PointHitTestParameters(point_MouseDown));

                for (int i = 0; i < hitResultsList.Count; i++)
                {
                    TextBlock tb = hitResultsList[i] as TextBlock;
                    if (tb == null) continue;
                    if (tb.Text == "Cancel")
                    {
                        Cancel_Click(); 
                    }
                }

List<DependencyObject> hitResultsList = new List<DependencyObject>();

    // 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;
    }

//清除用于命中测试结果的列表的内容。
hitResultsList.Clear（）；
//设置回调以接收命中测试结果枚举。
VisualTreeHelper.HitTest（pe.InkCanvas，null，
新的HitTestResultCallback（MyHitTestResult），新的PointHitTestParameters（point_MouseDown））；
for（int i=0；i

// 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(pe.InkCanvas, null,
                    new HitTestResultCallback(MyHitTestResult),                        new PointHitTestParameters(point_MouseDown));

                for (int i = 0; i < hitResultsList.Count; i++)
                {
                    TextBlock tb = hitResultsList[i] as TextBlock;
                    if (tb == null) continue;
                    if (tb.Text == "Cancel")
                    {
                        Cancel_Click(); 
                    }
                }

List<DependencyObject> hitResultsList = new List<DependencyObject>();

    // 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;
    }

List hitsresultslist=new List（）；
//将命中测试的结果返回回叫。
公共HitTestResultBehavior MyHitTestResult（HitTestResult）
{
//将命中测试结果添加到枚举后要处理的列表中。
hitResultsList.Add（result.VisualHit）；
//将行为设置为在所有z顺序级别返回视觉效果。
返回HitTestResultBehavior。是否继续；
}

---

---

有更好的办法吗？为什么按钮显示为文本块？

您可以共享您的xaml树吗？因此，我们可以看一看，并尝试模拟。