title: WPF MouseDown on Datagrid => Get Column and Row
body: <p>how can I recognize where I click on <code>DataGrid</code>?</p>
  
  <pre><code>&lt;DataGrid x:Name="TheGrid" SelectionMode="Single" SelectionUnit="Cell" MouseDown="CellClick"&gt;
  
  private void CellClick(object sender, MouseButtonEventArgs e)
  {
      foreach (DataGridCellInfo cell in TheGrid.SelectedCells)
      {
          MessageBox.Show(TheGrid.Items.IndexOf(cell.Item).ToString());
      }
  }
  </code></pre>
  
  <p>many thanks</p>