如何在WPF和Silverlight中取得DataTemplate中的命名元素

WPF

1.假如ListBox使用如下的DataTemplate

<DataTemplate x:Key="myDataTemplate">
  <TextBlock Name="textBlock" FontSize="14" Foreground="Blue">
    <TextBlock.Text>
      <Binding XPath="Title"/>
    </TextBlock.Text>
  </TextBlock>
</DataTemplate>

2.在cs文件中写如下的代码可以找到某个ListBoxItem对应的TextBlock

ListBoxItem myListBoxItem =
    (ListBoxItem)(myListBox.ItemContainerGenerator.ContainerFromItem(myListBox.Items.CurrentItem));

ContentPresenter myContentPresenter = FindVisualChild<ContentPresenter>(myListBoxItem);

DataTemplate myDataTemplate = myContentPresenter.ContentTemplate;
TextBlock myTextBlock = (TextBlock)myDataTemplate.FindName("textBlock", myContentPresenter);
MessageBox.Show("The text of the TextBlock of the selected list item: "
    + myTextBlock.Text);

private childItem FindVisualChild<childItem>(DependencyObject obj)
    where childItem : DependencyObject
{
    for (int i = 0; i < VisualTreeHelper.GetChildrenCount(obj); i++)
    {
        DependencyObject child = VisualTreeHelper.GetChild(obj, i);
        if (child != null && child is childItem)
            return (childItem)child;
        else
        {
            childItem childOfChild = FindVisualChild<childItem>(child);
            if (childOfChild != null)
                return childOfChild;
        }
    }
    return null;
}

SilverLight

1. Xmal 和WPF中相同

2. 由于SL中的DataTemplate没有FindName方法，因此c#代码有所区别

ListBoxItem myListBoxItem =
    (ListBoxItem)(myListBox.ItemContainerGenerator.ContainerFromItem(myListBox.Items.CurrentItem));

TextBlock myTextBlock = FindFirstVisualChild<TextBlock>(_myListBoxItem , "textBlock");
MessageBox.Show("The text of the TextBlock of the selected list item: "
    + myTextBlock.Text);

private childItem FindVisualChild<childItem>(DependencyObject obj,String childName)
    where childItem : DependencyObject
{
    for (int i = 0; i < VisualTreeHelper.GetChildrenCount(obj); i++)
    {
        DependencyObject child = VisualTreeHelper.GetChild(obj, i);
        if (child != null && child is childItem && child.GetValue(NameProperty).ToString()==childName)
            return (childItem)child;
        else
        {
            childItem childOfChild = FindVisualChild<childItem>(child,childName);
            if (childOfChild != null)
                return childOfChild;
        }
    }
    return null;
}