title: Set Interaction.Triggers to ListBoxItem
body: <p>I have set Interaction.Triggers to ListBox and perform respective TargetedTriggerAction when 'SelectionChanged' event occurs, like below.</p>
  
  <pre><code>&lt;ListBox x:Name="WorksheetListBox" ItemsSource="{Binding WorkSheetCollection}"
                               ItemTemplate="{StaticResource workSheetTemplate}"&gt;                              
    &lt;i:Interaction.Triggers&gt;
      &lt;i:EventTrigger EventName="SelectionChanged"&gt;
          &lt;action:WorksheetListBoxAction /&gt;
      &lt;/i:EventTrigger&gt;
    &lt;/i:Interaction.Triggers&gt;
  &lt;/ListBox&gt;
  </code></pre>
  
  <p>But my requirement is I need to set Interaction.Triggers to ListBoxItem's 'PreviewMouseDown' event(Note: ListBox populated via ItemsSource)</p>