private void StackPanel_Tap(object sender, TappedRoutedEventArgs e)

    {

         //获取到的对象是ListBoxItem

         ListBoxItem myListBoxItem =  (ListBoxItem)(listbox.ItemContainerGenerator.ContainerFromItem((sender as Panel).DataContext));

         // 在ListBoxItem中查找ContentPresenter

         ContentPresenter myContentPresenter = FindVisualChild<ContentPresenter>(myListBoxItem);

        ……//省略若干代码

    }

    //查找可视化树某个类型的元素

    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;

    }