title: How to get Binding value of current cell in a WPFToolkit DataGrid
body: <p>I want to change the foreground color of cells that hold negative numbers, but I don't know how to specify the DataTrigger that would let me. I'm using something like this:</p>
  
  <pre><code>&lt;Style x:Key="NumberCellStyle" BasedOn="{StaticResource CellStyle}"&gt;
      &lt;Style.Triggers&gt;
          &lt;DataTrigger Binding="{Binding Converter={StaticResourceExtension SignConverter}}" Value="-1"&gt;
              &lt;Setter Property="TextBlock.Foreground" Value="Red"/&gt; 
          &lt;/DataTrigger&gt;
      &lt;/Style.Triggers&gt;
  &lt;/Style&gt;
  </code></pre>
  
  <p>But in the SignConverter converter I get the whole ViewModel instead of the numeric value I want to convert. I want this to work across the app, without me needing to specify the correct Path for each binding.</p>
  
  <p>Thank you very much!</p>