<ListBox Name="myListBox" ItemTemplate="{StaticResource myDataTemplate}"
         IsSynchronizedWithCurrentItem="True">
  <ListBox.ItemsSource>
    <Binding Source="{StaticResource InventoryData}" XPath="Books/Book"/>
  </ListBox.ItemsSource>
</ListBox>

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

			' Getting the currently selected ListBoxItem
			' Note that the ListBox must have
			' IsSynchronizedWithCurrentItem set to True for this to work
			Dim myListBoxItem As ListBoxItem = CType(myListBox.ItemContainerGenerator.ContainerFromItem(myListBox.Items.CurrentItem), ListBoxItem)

			' Getting the ContentPresenter of myListBoxItem
			Dim myContentPresenter As ContentPresenter = FindVisualChild(Of ContentPresenter)(myListBoxItem)

			' Finding textBlock from the DataTemplate that is set on that ContentPresenter
			Dim myDataTemplate As DataTemplate = myContentPresenter.ContentTemplate
			Dim myTextBlock As TextBlock = CType(myDataTemplate.FindName("textBlock", myContentPresenter), TextBlock)

			' Do something to the DataTemplate-generated TextBlock
			MessageBox.Show("The text of the TextBlock of the selected list item: " & myTextBlock.Text)

// Getting the currently selected ListBoxItem
// Note that the ListBox must have
// IsSynchronizedWithCurrentItem set to True for this to work
ListBoxItem myListBoxItem =
    (ListBoxItem)(myListBox.ItemContainerGenerator.ContainerFromItem(myListBox.Items.CurrentItem));

// Getting the ContentPresenter of myListBoxItem
ContentPresenter myContentPresenter = FindVisualChild<ContentPresenter>(myListBoxItem);

// Finding textBlock from the DataTemplate that is set on that ContentPresenter
DataTemplate myDataTemplate = myContentPresenter.ContentTemplate;
TextBlock myTextBlock = (TextBlock)myDataTemplate.FindName("textBlock", myContentPresenter);

// Do something to the DataTemplate-generated TextBlock
MessageBox.Show("The text of the TextBlock of the selected list item: "
    + myTextBlock.Text);

		Private Function FindVisualChild(Of childItem As DependencyObject)(ByVal obj As DependencyObject) As childItem
			For i As Integer = 0 To VisualTreeHelper.GetChildrenCount(obj) - 1
				Dim child As DependencyObject = VisualTreeHelper.GetChild(obj, i)
				If child IsNot Nothing AndAlso TypeOf child Is childItem Then
					Return CType(child, childItem)
				Else
					Dim childOfChild As childItem = FindVisualChild(Of childItem)(child)
					If childOfChild IsNot Nothing Then
						Return childOfChild
					End If
				End If
			Next i
			Return Nothing
		End Function

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;
}