title: WPF Toolkit DataGridCell Style DataTrigger
body: <p>I am trying to change the color of a cell to Yellow if the value has been updated in the DataGrid.</p>
  
  <p>My XAML:</p>
  
  <pre><code>&lt;toolkit:DataGrid x:Name="TheGrid"
                    ItemsSource="{Binding}"
                    IsReadOnly="False"
                    CanUserAddRows="False"
                    CanUserResizeRows="False"
                    AutoGenerateColumns="False"
                    CanUserSortColumns="False"                             
                    SelectionUnit="CellOrRowHeader" 
                    EnableColumnVirtualization="True" 
                    VerticalScrollBarVisibility="Auto"
                    HorizontalScrollBarVisibility="Auto"&gt;
      &lt;toolkit:DataGrid.CellStyle&gt;
          &lt;Style TargetType="{x:Type toolkit:DataGridCell}"&gt;
              &lt;Style.Triggers&gt;
                  &lt;DataTrigger Binding="{Binding IsDirty}" Value="True"&gt;
                      &lt;Setter Property="Background" Value="Yellow"/&gt;
                   &lt;/DataTrigger&gt;
              &lt;/Style.Triggers&gt;
          &lt;/Style&gt;
      &lt;/toolkit:DataGrid.CellStyle&gt;
  &lt;/toolkit:DataGrid&gt;
  </code></pre>
  
  <p>The grid is bound to a List of arrays (displaying a table of values kind of like excel would). Each value in the array is a custom object that contains an IsDirty dependency property. The IsDirty property gets set when the value is changed.</p>
  
  <p>When i run this:</p>
  
  <ul>
  <li>change a value in column 1 = whole row goes yellow</li>
  <li>change a value in any other column = nothing happens</li>
  </ul>
  
  <p>I want only the changed cell to go yellow no matter what column its in. Do you see anything wrong with my XAML?</p>