Cannot begin storyboard based on ListBoxItem selection???

 

  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 x:Class="WpfApplication1.MainWindow"
 x:Name="Window"
 Title="MainWindow"
 Width="640" Height="480">
 

  
  
  
  
    
   
     XPath=@icon}" />
     XPath=@name}" />
    
  
  
   
     XPath=@icon}" />
     XPath=@name}" />
    
  
 
 
  
  
 
 
   
    
    
   
   
    
    
   
   
    
    
   
  
  
 
   
    
    
   
   
    
    
   
   
    
    
   
  

  
  
         
          
         
                   SelectedValuePath="@UriSource"
          SelectedIndex="0"
          ItemsSource="{Binding Source={StaticResource PagesData}, XPath=page}" 
          ItemContainerStyle="{DynamicResource ListBoxItemContainerStyle}" 
          ClipToBounds="True" >