Programming ASP.NET, Second Edition

The Summary Validator

You have great control over how validation errors are reported. For example, rather than putting error messages alongside the control, you can 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 popup message box.

Let’s rewrite Example 8-1 to add a ValidationSummary control at the bottom of the page. This simply requires that you add the code shown in boldface after the </table> tag as shown in the code snippet from Example 8-1:

</table>
<asp:ValidationSummary ID="ValSum" DisplayMode="BulletList"
runat="server" HeaderText="The following errors were found: "
ShowMessageBox="True" ShowSummary="True"></asp:ValidationSummary>

Here you’ve named the ValidationSummary control ValSum and set its DisplayMode property to BulletList. The HeaderText attribute holds the header that will be displayed only if there are errors to report. You can mix the ShowMessageBox and ShowSummary attributes to display the errors in the body of the HTML document (ShowSummary="true“) or in a pop-up message box (ShowMessageBox="true“) or both.

To make this work, you’ll need to add an ErrorMessage attribute to the other validation controls. For example, you might modify the first validation control as follows:

<td align=middle rowspan=1> <asp: RequiredFieldValidator id="reqFieldBooks" ControlToValidate="ddlBooks" Display="static" InitialValue="-- ...