如何從代碼隱藏中訪問我的ItemPanelTemplate中的命名控件？

Question

我試圖訪問ItemsPanelTemplate內的Canvas對象，所以我可以直接在代碼隱藏中添加項目。

這是我的XAML：

<ListBox x:Name="MyMap" ItemsSource="{Binding MapItems}" 
     Background="Gray" 
     SelectionChanged="MyMap_SelectionChanged"> 

    <ListBox.ItemsPanel> 
     <ItemsPanelTemplate> 
      <Canvas x:Name="MyMapCanvas" 
      HorizontalAlignment="Left" 
      VerticalAlignment="Top" 
      Background="Transparent"> 
      </Canvas> 
     </ItemsPanelTemplate> 
    </ListBox.ItemsPanel> 

如何訪問「MyMapCanvas」中的代碼隱藏項補充呢？

我曾嘗試以下：

Canvas canvas = (Canvas)MyMap.ItemsPanel.LoadContent(); 

和

ContentPresenter cp = (ContentPresenter)(VisualTreeHelper.GetChild(MyMap, 0)); 
ItemsPanelTemplate ipt = MyMap.ItemsPanel; 
Canvas canvas = ipt.FindName("MyMapCanvas", cp) as Canvas; 

在此先感謝。

Answer 1

試試這個：

//your OnLoaded handler 
    private void MainWindow_OnLoaded(object sender, RoutedEventArgs e) 
    { 
     Canvas canvas = FindVisualChild<Canvas>(MyMap); 
    } 

    public TChildItem FindVisualChild<TChildItem>(DependencyObject obj) where TChildItem : DependencyObject 
    { 
     for (int i = 0; i < VisualTreeHelper.GetChildrenCount(obj); i++) 
     { 
      var child = VisualTreeHelper.GetChild(obj, i); 

      if (child != null && child is TChildItem) 
       return (TChildItem)child; 

      var childOfChild = FindVisualChild<TChildItem>(child); 

      if (childOfChild != null) 
       return childOfChild; 
     } 

     return null; 
    }