Programming ASP.NET 3.5, 4th Edition

The Summary Control

You can decide how and where validation errors are reported. You are not required to place validator controls alongside the control they are validating, although it does help to identify which text box or list control has been filled out incorrectly. For forms of any size, though, a good strategy to help a user identify her mistakes is to summarize all the validation failures with a ValidationSummary control. This control can place a summary of the errors in a bulleted list, a simple list, or a paragraph that appears on the web page or in a pop-up message box.

To demonstrate, add to the website a new page called ValidationSummary.aspx and copy the contents of RequiredFieldValidator.aspx into it. Add a ValidationSummary control at the bottom of the page, between the closing </table> and </form> tags.

...
      <tr>
         <td colspan="3" align="center">
            <asp:Button ID="btnSubmit" Text="Submit Bug" runat="server" />
         </td>
      </tr>
   </table>
   <asp:ValidationSummary ID="ValidationSummary1" runat="server"
      DisplayMode="BulletList"
      HeaderText="The following errors were found: "
      ShowSummary="true" />
   </form>
</body>
</html>

Three properties are set on the ValidationSummary control besides the mandatory runat and ID:

DisplayMode

Sets the way in which those errors are shown in the summary. Possible values are BulletList (shown in Figure 11-3), List, and SingleParagraph.

HeaderText

Sets the header that will be displayed if there are any errors to report.

ShowSummary

Indicates that the errors ...