title: Datagrid datatrigger not fired when value changes
body: <p>I have a dataGridwith columns that have bindings to some columns in a data table</p>
  
  <pre><code>&lt;DataGrid x:Name="WatchersGrid" ItemsSource="{Binding GroupWatchers}" AutoGenerateColumns="False" SelectedItem="{Binding SelectedItem}" &gt;
              &lt;DataGrid.Columns&gt;
                  &lt;DataGridTextColumn Header="Name" Binding="{Binding  Path=[Name]}"/&gt;
                          &lt;DataGridTextColumn Header="Value" Binding="{Binding Path=[Value]}"&gt;
                              &lt;DataGridTextColumn.ElementStyle&gt;
                                  &lt;Style&gt;
                                      &lt;Setter Property="TextBlock.TextWrapping" Value="Wrap"/&gt;
                                  &lt;/Style&gt;
                              &lt;/DataGridTextColumn.ElementStyle&gt;
                          &lt;/DataGridTextColumn&gt;
                          &lt;DataGridTextColumn Header="InRange" Binding="{Binding [IsInRange]}"/&gt;
              &lt;/DataGrid.Columns&gt;
                      &lt;DataGrid.RowStyle&gt;
                          &lt;Style TargetType="DataGridRow"&gt;
                              &lt;Style.Triggers&gt;
                                  &lt;DataTrigger Binding="{Binding [IsInRange]}" Value="False"&gt;
                                      &lt;Setter Property="Foreground" Value="Crimson"&gt;&lt;/Setter&gt;
                                  &lt;/DataTrigger&gt;
                              &lt;/Style.Triggers&gt;
                          &lt;/Style&gt;
                      &lt;/DataGrid.RowStyle&gt;
          &lt;/DataGrid&gt;
  </code></pre>
  
  <p>i have a data trigger on the "IsInRange" column that sets the foreground property to red if the value is false.
  the value inside the data grid column changes but the color property dosent change.
  i tried to    NotifyPropertyChanged("[IsInRange]"); when my value is changing but that didnt help
  any ideas?</p>
  
  <p>Edit:
  My ViewModel</p>
  
  <pre><code>public class WatcherControlViewModel : INotifyPropertyChanged
  {
    private DataTable _dt;
    private string _groupName;
    public DataRow[] GroupWatchers{get {return _dt.Select("Group = '" + GroupName + "'");}}
    public WatcherControlViewModel(DataTable dt, string name)
      {
          _dt = dt;
          _groupName = name;
         _dt.RowChanged += DataTableChangedEvent;
      }
  
      private void DataTableChangedEvent(object sender, DataRowChangeEventArgs e)
      {
          NotifyPropertyChanged("GroupWatchers");
          NotifyPropertyChanged("IsInRange");
      }
  }
  </code></pre>
  
  <p>thanks</p>