title: Change wpf style from viewmodel
body: <p>I have a DataTemplate:</p>
  
  <pre><code> &lt;DataTemplate
              DataType="{x:Type local:ConnectionViewModel}"
              &gt;
              &lt;!-- The connection is represented by a curved arrow. --&gt;
              &lt;ca:CurvedArrow
  
                      StrokeThickness="2"
                      Points="{Binding Points}"
                      Fill="{StaticResource connectionBrush}"
                      Stroke="{StaticResource connectionBrush}"
                  /&gt;
  
          &lt;/DataTemplate&gt;
  </code></pre>
  
  <p>This represent all the connector i have in my view.
  What I want to do is to set a different fill and stroke for specific <strong>specific</strong> connectors from the viewmodel. 
  How can I achive that?</p>