title: Binding DataGridCell ToolTip property to value of DataGridCell
body: <p>I have <code>DataGrid</code> and one of the <code>DataGrid</code> columns looks like this</p>
  
  <pre><code>&lt;DataGridTextColumn Header="Value" 
          Binding="{Binding Value, Converter={StaticResource BooleanToYesNoConverter}}" 
          x:Name="_col2" 
          IsReadOnly="True"
          CanUserSort="False"
          Width="*"&gt;
      &lt;DataGridTextColumn.CellStyle&gt;
          &lt;Style TargetType="DataGridCell"&gt;
              &lt;Setter Property="ToolTip" Value="{Binding Value, Converter={StaticResource BooleanToYesNoConverter}}" /&gt;
          &lt;/Style&gt;
      &lt;/DataGridTextColumn.CellStyle&gt;
  &lt;/DataGridTextColumn&gt;
  </code></pre>
  
  <p>The problem is I forced to use <code>BooleanToYesNoConverter</code> converter twice. It means that <code>Convert</code> method of <code>BooleanToYesNoConverter</code> will be invoked twice. Therefore, I want to optimize my code. And want to bind value of <code>ToolTip</code> property directly to value of cell.</p>
  
  <p>I tried approach with using <code>ElementName</code>-s. But I have no idea what should I specify in <strong>Path</strong> property of binding.</p>
  
  <pre><code>&lt;DataGridTextColumn Header="Value" 
          Binding="{Binding Value, Converter={StaticResource BooleanToYesNoConverter}}" 
          x:Name="_col2" 
          IsReadOnly="True"
          CanUserSort="False"
          Width="*"&gt;
      &lt;DataGridTextColumn.CellStyle&gt;
          &lt;Style TargetType="DataGridCell"&gt;
              &lt;Setter Property="ToolTip" Value="{Binding ElementName=_col2, Path=???}" /&gt;
          &lt;/Style&gt;
      &lt;/DataGridTextColumn.CellStyle&gt;
  &lt;/DataGridTextColumn&gt;
  </code></pre>
  
  <p>I tried to use <code>DataGridTemplateColumn</code> instead of <code>DataGridTextColumn</code>, but it does't work too.</p>
  
  <pre><code>&lt;DataGridTemplateColumn CanUserSort="False"
                          Header="Значение"
                          Width="*"&gt;
      &lt;DataGridTemplateColumn.CellTemplate&gt;
          &lt;DataTemplate&gt;
              &lt;TextBlock Text="{Binding Value, Converter={StaticResource BooleanToYesNoConverter}}"
                          Name="_textBlock"/&gt;    
          &lt;/DataTemplate&gt;
      &lt;/DataGridTemplateColumn.CellTemplate&gt;
      &lt;DataGridTemplateColumn.CellStyle&gt;
          &lt;Style TargetType="DataGridCell"&gt;
              &lt;Setter Property="ToolTip" Value="{Binding RelativeSource ElementName=_textBlock, Path=Text}" /&gt;
          &lt;/Style&gt;
      &lt;/DataGridTemplateColumn.CellStyle&gt;
  &lt;/DataGridTemplateColumn&gt;
  </code></pre>
  
  <p>How can I solve my task. Is it possible at all?</p>