silverlight：ListBox中如何取得DateTemplate/ItemsPanelTemplate中的命名控件?

Xaml如下:

<UserControl x:Class="ToolsTest.Test"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    Width="400" Height="300">
    <UserControl.Resources>
        <DataTemplate x:Key="dt">
            <TextBlock Padding="5,0,5,0"  Text="{Binding d}" x:Name="myTxt"/>
        </DataTemplate>
    </UserControl.Resources>
    <StackPanel>
        <ListBox Name="myListBox" ItemTemplate="{StaticResource dt}" />      
        <Button Content="查找myTxt" x:Name="btnFind" Width="90" Click="btnFind_Click"></Button>
    </StackPanel>
</UserControl>

Xaml.cs如下:

using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;

namespace ToolsTest
{
    public partial class Test : UserControl
    {
        ObservableCollection<TestData> oc;

        public Test()
        {
            InitializeComponent();
            this.Loaded += new RoutedEventHandler(Test_Loaded);
        }

        void Test_Loaded(object sender, RoutedEventArgs e)
        {
            oc = new ObservableCollection<TestData>();
            oc.Add(new TestData() { d = "A" });
            oc.Add(new TestData() { d = "B" });
            this.myListBox.ItemsSource = oc;
        }       

        private void btnFind_Click(object sender, RoutedEventArgs e)
        {
            if (myListBox.SelectedItem != null)
            {
                ListBoxItem _selectedItem = (ListBoxItem)(myListBox.ItemContainerGenerator.ContainerFromItem(myListBox.SelectedItem));
                TextBlock myTxt = FindFirstVisualChild<TextBlock>(_selectedItem, "myTxt");
                MessageBox.Show(string.Format("选中行的TextBlock值为：" + myTxt.Text));
            }
           

            ListBoxItem _firstItem = (ListBoxItem)(myListBox.ItemContainerGenerator.ContainerFromItem(myListBox.Items[0]));

            //var t =  _firstItem.FindName("myTxt");//这样是找不到的
            TextBlock myTxtFirst = FindFirstVisualChild<TextBlock>(_firstItem, "myTxt");
            MessageBox.Show(string.Format("第一行的TextBlock值为：" + myTxtFirst.Text));
        }
       

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

    public class TestData{public string d{set;get;}}
}

这里我们借助VisualTreeHelper对指定行(ListBoxItem)做了一个遍历，以查找符合要求的控件

对于ItemsPanelTemplate中的命名控件，比如下面这样的:

<ListBox>
            <ItemsPanelTemplate>
                <StackPanel Orientation="Horizontal" x:Name="sp"></StackPanel>
            </ItemsPanelTemplate>
            
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <Rectangle Width="100" Height="100" Fill="{Binding Color}" x:Name="listItem" MouseLeftButtonDown="listItem_MouseLeftButtonDown"></Rectangle>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>

如果想在listItem_MouseLeftButtonDown中引用sp，按正统处理方法还真是比较麻烦(各位可以google,baidu印证)，这里给出一个很取巧的办法：
<ItemsPanelTemplate>
        <StackPanel Orientation="Horizontal" x:Name="sp" Loaded="sp_Loaded"></StackPanel>
</ItemsPanelTemplate>
然后在后端代码中，添加一个私有变量，并处理sp_Loaded事件:

 StackPanel _sp = null;
 private void sp_Loaded(object sender, RoutedEventArgs e)
 {
     _sp = sender as StackPanel;
 }

这样，在listItem_MouseLeftButtonDown中就能借助"_sp"正确引用到ItemsPanelTemplate中的sp了