title: Winforms: Problems validating a cell in a datagridview
body: <p>I want to validate a Winforms <strong>datagridview</strong> cell with <strong>CellValidating</strong>. If a value was not set correctly by the user I set <strong>ErrorText</strong> and use <code>e.Cancel</code>, so that the cursor remains in the cell.
  The problem is now, that the <strong>error-symbol</strong> (and the <strong>error text</strong>) is not displayed (in the cell). When I delete e.Cancel the cell looses the focus and error-symbol is displayed. How can I achieve that the cell remains in edit mode and the error-symbol is displayed too?</p>
  
  <pre><code>if (...)
  {
     this.datagridviewX.Rows[e.RowIndex].Cells[e.ColumnIndex].ErrorText = "Errortext";
     e.Cancel = true;
  }
  else
  {
     this.datagridviewX.Rows[e.RowIndex].Cells[e.ColumnIndex].ErrorText = "";
  }
  </code></pre>