title: Show row number in row header of a DataGridView
body: <p>Is it possible to show row number in the row header of a <code>DataGridView</code>?        </p>
  
  <p>I'm trying with this code, but it doesn't work:</p>
  
  <pre><code>    private void setRowNumber(DataGridView dgv)
      {
          foreach (DataGridViewRow row in dgv.Rows)
          {
              row.HeaderCell.Value = row.Index + 1;
          }
      }
  </code></pre>
  
  <p>Do I have to set some <code>DataGridView</code> property?</p>