title: DataTrigger for Textblock
body: <p>I have a Textblock that I'm trying to change the value of the Text property if a property is True or False.  The issue I'm having is that the flag could be changed on different events on the screen (onchange events from other combo boxes).</p>
  
  <p>I'm not sure how to get this datatrigger to work as I don't think it know when the value has been changed.</p>
  
  <pre><code>&lt;TextBlock Grid.Row="9" HorizontalAlignment="Right" Text="Some Old Value:" VerticalAlignment="Center"&gt;
      &lt;TextBlock.Style&gt;
          &lt;Style TargetType="{x:Type TextBlock}"&gt;
               &lt;Style.Triggers&gt;
                   &lt;DataTrigger Binding="{Binding IsChecked}" Value="False" &gt;
                       &lt;Setter Property="Text" Value="Different Text:"/&gt;
                   &lt;/DataTrigger&gt;
               &lt;/Style.Triggers&gt;
           &lt;/Style&gt;
       &lt;/TextBlock.Style&gt;                                
  &lt;/TextBlock&gt;
  </code></pre>
  
  <p>I see in some comboboxes there is the <code>UpdateSourceTrigger=PropertyChanged</code>, but I don't see a way to implement that in the TextBlock. </p>