title: setting text on DataGridTextColumn
body: <p>I am using a DataTrigger to  replace empty cells with '-' text. My code:</p>
  
  <pre><code>  &lt;DataGridTextColumn Header="Time taken" Binding="{Binding Path=finish}" Width="Auto" x:Name="x"&gt;
       &lt;DataGridTextColumn.ElementStyle&gt;
            &lt;Style TargetType="{x:Type TextBlock}"&gt;
                &lt;Style.Triggers&gt;
                    &lt;DataTrigger Binding="{Binding Path=finish}" Value="{x:Null}"&gt;
                         &lt;Setter Property="TextBlock.Text" Value="-" /&gt;
                     &lt;/DataTrigger&gt;
                 &lt;/Style.Triggers&gt;
              &lt;/Style&gt;
       &lt;/DataGridTextColumn.ElementStyle&gt;
    &lt;/DataGridTextColumn&gt;
  </code></pre>
  
  <p>But I couldn't find the text being set. I tried  changing the background of the TextBlock and its working. Why cant I set the Text property?</p>