Silverlight工具包Treeview：獲取所選項目的父項

Question

我使用Silverlight工具包中的TreeView組件，並試圖獲取選定節點的父項。 TreeView綁定到一系列對象，所以直接使用TreeViewItem似乎是不可能的。

<toolkit:TreeView SelectedItemChanged="DoStuff" DisplayMemberPath="Name" ItemsSource="{Binding MyCollection}"> 
    <toolkit:TreeView.ItemTemplate> 
     <common:HierarchicalDataTemplate ItemsSource="{Binding MySubCollection}"> 
      <StackPanel> 
       <TextBlock Text="{Binding Name}" /> 
      </StackPanel> 
     </common:HierarchicalDataTemplate> 
    </toolkit:TreeView.ItemTemplate> 
</toolkit:TreeView> 

有沒有辦法獲取在DoStuff事件中選擇的項目的父項？

Answer 1

只要你下載了最新的Silverlight工具包，那麼這是很容易使用包含的TreeViewExtensions。

1. 下載Silverlight Toolkit並安裝。
2. 添加到System.Windows.Controls.Toolkit參考（從Silverlight工具包）

3. 使用GetParentItem（）擴展方法，像這樣：

   private void DoStuff(object sender, RoutedPropertyChangedEventArgs<object> e) 
   { 
       if (e.NewValue != null) 
       { 
        var parent = ((TreeView)sender).GetParentItem(e.NewValue); 
        // 
        // Do stuff with parent, this snippet updates 
        // a TextBlock showing the name of the current parent 
        if (parent != null) 
        { 
         Status.Text = parent.ToString(); 
        } 
       } 
   } 
   

Answer 2

爲什麼不只是讓MySubcollection中的對象保持對父對象的引用？

Answer 3

假設你的樹的名字是「樹」，這應該做的伎倆

((tree.SelectedItem as TreeViewItem).Parent as SomeObjectOfYours) 

Answer 4

Justin Angel寫了一篇關於「先進」的TreeView使用，其中包括通過其綁定對象發現在一個TreeView arbirtraty元素。 因爲我對Silverlight來說比較新，所以我不確定是否有更好，更優雅的方法，但是可以使用他的方法之一來查找父項。

我想用電話這種方式：

TreeViewItem trvi = ContainerFromItem(tree, tree.SelectedItem); 
MySubCollectionItem parentItem = ItemFromContainer(tree, trvi.Parent); // note the "Parent" here 

下面提供的擴展方法從什麼地方：

public static TreeViewItem ContainerFromItem(this TreeView treeView, object item) 
{ 
    TreeViewItem containerThatMightContainItem = (TreeViewItem)treeView.ItemContainerGenerator.ContainerFromItem(item); 
    if (containerThatMightContainItem != null) 
     return containerThatMightContainItem; 
    else 
     return ContainerFromItem(treeView.ItemContainerGenerator, treeView.Items, item); 
} 

private static TreeViewItem ContainerFromItem(ItemContainerGenerator parentItemContainerGenerator, ItemCollection itemCollection, object item) 
{ 
    foreach (object curChildItem in itemCollection) 
    { 
     TreeViewItem parentContainer = (TreeViewItem)parentItemContainerGenerator.ContainerFromItem(curChildItem); 
     if (parentContainer == null) 
      return null; 
     TreeViewItem containerThatMightContainItem = (TreeViewItem)parentContainer.ItemContainerGenerator.ContainerFromItem(item); 
     if (containerThatMightContainItem != null) 
      return containerThatMightContainItem; 
     TreeViewItem recursionResult = ContainerFromItem(parentContainer.ItemContainerGenerator, parentContainer.Items, item); 
     if (recursionResult != null) 
      return recursionResult; 
    } 
    return null; 
} 

public static object ItemFromContainer(this TreeView treeView, TreeViewItem container) 
{ 
    TreeViewItem itemThatMightBelongToContainer = (TreeViewItem)treeView.ItemContainerGenerator.ItemFromContainer(container); 
    if (itemThatMightBelongToContainer != null) 
     return itemThatMightBelongToContainer; 
    else 
     return ItemFromContainer(treeView.ItemContainerGenerator, treeView.Items, container); 
} 

private static object ItemFromContainer(ItemContainerGenerator parentItemContainerGenerator, ItemCollection itemCollection, TreeViewItem container) 
{ 
    foreach (object curChildItem in itemCollection) 
    { 
     TreeViewItem parentContainer = (TreeViewItem)parentItemContainerGenerator.ContainerFromItem(curChildItem); 
     if (parentContainer == null) 
      return null; 
     TreeViewItem itemThatMightBelongToContainer = (TreeViewItem)parentContainer.ItemContainerGenerator.ItemFromContainer(container); 
     if (itemThatMightBelongToContainer != null) 
      return itemThatMightBelongToContainer; 
     TreeViewItem recursionResult = ItemFromContainer(parentContainer.ItemContainerGenerator, parentContainer.Items, container) as TreeViewItem; 
     if (recursionResult != null) 
      return recursionResult; 
    } 
    return null; 
}