How do I add an additional CSS class on a surrounding DIV for failed form validation?
<p>Here's my scenario:</p>

<pre><code>  &lt;!-- Normal Control --&gt;
  &lt;div class="required"&gt;
    &lt;label for="address1"&gt;Address line 1&lt;/label&gt;
    &lt;input type="text id="address1" name="address1" class="inputText" /&gt;
  &lt;/div&gt;

  &lt;!-- Same Control - but with a validation error --&gt;
  &lt;div class="required error"&gt;
    &lt;p class="error"&gt;Address Line 1 Field is required&lt;/p&gt;
    &lt;label for="address1"&gt;Address line 1&lt;/label&gt;
    &lt;input type="text id="address1" name="address1" class="inputText" /&gt;
  &lt;/div&gt;
</code></pre>

<p>In the "validation error" html area, I'm able to show the message using code like this:</p>

<pre><code>  &lt;div class="required"&gt;
    &lt;asp:RequiredFieldValidator id="address1_validate" runat="server" ControlToValidate="address1" Text='&lt;p class="error"&gt;Address Line 1 Field is required&lt;/p&gt;' /&gt;
    &lt;label for="address1"&gt;Address (line 1)&lt;/label&gt;
    &lt;asp:TextBox id="address1" CssClass="inputText" CausesValidation="true" runat="server"/&gt;
  &lt;/div&gt;
</code></pre>

<p>What I'm not able to do is add the additional class to the surrounding div tag.
I was thinking that I could do something like:</p>

<pre><code>  &lt;div class="required &lt;%= !address1_validate.isValid ? "error" : "" %&gt;"&gt;
</code></pre>

<p>That pretty much doesn't work.</p>

<p>Anyway, I don't want to have to rely on JavaScript to set these values - it needs to work like "Web 1.0".</p>

<p>Any ideas?</p>

<p>Thanks,
Jon</p>

<p>------- My Solution-------
Here's the code behind that worked for me:</p>

<pre><code>  protected void Page_Load(object sender, EventArgs e)
  {
    if (this.IsPostBack)
    {
      address1_validate.Validate();
      if (!address1_validate.IsValid)
      {
        address_panel.CssClass = "required error";
      }
    }
  }
</code></pre>

<p>And the front-end:</p>

<pre><code>  &lt;asp:Panel runat="server" id="address_panel" CssClass="required"&gt;
    &lt;asp:RequiredFieldValidator id="address1_validate" runat="server" ControlToValidate="address1" Text='&lt;p class="error"&gt;Address Field is required&lt;/p&gt;' /&gt;
    &lt;label for="address1"&gt;Address (line 1)&lt;/label&gt;
    &lt;asp:TextBox id="address1" CssClass="inputText" CausesValidation="true" EnableViewState="true" runat="server"  /&gt;
  &lt;/asp:Panel&gt;
</code></pre>

<p>Thanks for the help!</p>
