InkCanvas的儿童点击测试

Question

我通过代码隐藏的方式向InkCanvas添加了一个按钮。至于原因，我无法理解，

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

在按钮具有指数为2，结果总是在结果为空时，我点击了按钮。

有人知道如何确定子元素是否被点击过？

任何帮助将不胜感激。 （是的，我已经搜索了互联网没有成功，我很抱歉，如果这似乎是一个愚蠢的问题）。

系统：Windows 7，.net4.0 WPF C＃

编辑：如果我这样做，让孩子[0]是一个RichTextBox，那么上述的HitTest resturns非空同样的事情。任何人有任何想法为什么？

编辑：两个RichTextBox的和按钮的代码隐藏添加的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> 

Answer 1

这工作，但似乎令人费解，我不知道为什么一个按钮显示为一个TextBlock ：

........... 

    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，在的PreviewMouseLeftButtonDown（）（代码略从微软的网站修改） ...............

................................................ ...

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; 
    } 

---

有没有更好的办法？为什么按钮显示为TextBlock？