title: ListBox Slide Animation On New Item Added
body: <p>I am working on a news feed. This will update every so often and if new items are found, I want to slide in the new content from the top.</p>
  
  <p>Right now, I am just having it fade in by doing the following:</p>
  
  <pre><code>&lt;ListBox Grid.Row="0" Height="Auto" HorizontalAlignment="Stretch" Margin="5,5,5,5"  VerticalAlignment="Top" ItemsSource="{Binding NewsItems,UpdateSourceTrigger=PropertyChanged}" &gt;
          &lt;ListBox.ItemContainerStyle&gt;                
              &lt;Style TargetType="{x:Type ListBoxItem}"&gt;                    
                  &lt;Style.Triggers&gt;                                        
                          &lt;EventTrigger RoutedEvent="Loaded"&gt;
                          &lt;EventTrigger.Actions&gt;                                
                              &lt;BeginStoryboard&gt;
                                  &lt;Storyboard&gt;                                      
                                      &lt;DoubleAnimation Storyboard.TargetProperty="Opacity" From="0" To="1" Duration="0:0:2" /&gt;     
                                  &lt;/Storyboard&gt;
                              &lt;/BeginStoryboard&gt;
                          &lt;/EventTrigger.Actions&gt;
                      &lt;/EventTrigger&gt;
                  &lt;/Style.Triggers&gt;
              &lt;/Style&gt;
              &lt;/ListBox.ItemContainerStyle&gt;
          &lt;ListBox.ItemTemplate&gt;    
          ....
  &lt;/ListBox&gt;
  </code></pre>
  
  <p>This works fine, but I would really like to have the item slide in. I have tried every possible thing I could find and cannot get anywhere. Any help would be much appreciated.</p>