title: Bind value from DataContext to converter parameter
body: <p>i have a problem:
  I have a datagrid. The DataContext of the grid is set to a collection called 'FinanceTransferEntries' which has a couple of fields. The code segment below shows the first column that is bound the the property 'ID' of the collection (which works fine). </p>
  
  <p>I implemented a converter that colors the background of the cell depending on </p>
  
  <ol>
  <li>a static boolen value "IDTransfer" --> works fine too</li>
  <li>and the value of the current cell of the field.</li>
  </ol>
  
  <p>Here is my problem. I didn't figure out the correct binding statement to access the current value of the 'ID' property.</p>
  
  <pre><code>    &lt;igDP:Field Name="ID" Label="ID" Width="Auto"  &gt;
          &lt;igDP:Field.Settings&gt;
              &lt;igDP:FieldSettings AllowEdit="False"&gt;
                  &lt;igDP:FieldSettings.EditorStyle&gt;
                      &lt;Style TargetType="{x:Type igEditors:XamTextEditor}" &gt;
                          &lt;Setter Property="Background"&gt;
                              &lt;Setter.Value&gt;
                                  &lt;MultiBinding Converter="{StaticResource DependentBackrgoundConverter}"&gt;
                                      &lt;Binding ? /&gt;
                                      &lt;Binding RelativeSource="{RelativeSource AncestorType={x:Type uc:TransferDataUC}}" Path="ViewModel.SelectedFinanceTransferViewModel.FinanceTransferDetailViewModel.IDTransfer" /&gt;
                                  &lt;/MultiBinding&gt;
                              &lt;/Setter.Value&gt;
                          &lt;/Setter&gt;
                      &lt;/Style&gt;
                  &lt;/igDP:FieldSettings.EditorStyle&gt;
              &lt;/igDP:FieldSettings&gt;
          &lt;/igDP:Field.Settings&gt;
      &lt;/igDP:Field&gt;
  </code></pre>
  
  <p>Help would be appreciated!</p>