Why isn't my CustomValidator in ASP.NET 4.0 working?
<p>The controls in the ASP.NET</p>

<pre><code>&lt;asp:TextBox ID="txtEnd" runat="server" placeholder="12:59"&gt;&lt;/asp:TextBox&gt;
&lt;asp:RadioButtonList ID="rblTime2" runat="server" RepeatDirection="Horizontal" RepeatLayout="Flow"&gt;
    &lt;asp:ListItem&gt;AM&lt;/asp:ListItem&gt;
    &lt;asp:ListItem&gt;PM&lt;/asp:ListItem&gt;
&lt;/asp:RadioButtonList&gt;
</code></pre>

<p>CustomValidator</p>

<pre><code>&lt;asp:CustomValidator ID="ValidateStartTime" ControlToValidate="txtEnd" OnServerValidate="ValidateStartTimeFun" runat="server" ErrorMessage="*required"&gt;&lt;/asp:CustomValidator&gt;
</code></pre>

<p>CodeBehind</p>

<pre><code>protected void ValidateStartTimeFun(object source, ServerValidateEventArgs args)
{
    try
    {   if (txtStart.Text != "" &amp;&amp; rblTime.SelectedValue != null )
        { args.IsValid = true; }}
    catch (Exception ex)
        { args.IsValid = false; }
}
</code></pre>

<p>It doesn't even give me a *required if I change the entire CodeBehind to this;</p>

<pre><code>protected void ValidateStartTimeFun(object source, ServerValidateEventArgs args)
{
    args.isValid = false;
}
</code></pre>
