Question

The controls in the ASP.NET

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

CustomValidator

<asp:CustomValidator ID="ValidateStartTime" ControlToValidate="txtEnd" OnServerValidate="ValidateStartTimeFun" runat="server" ErrorMessage="*required"></asp:CustomValidator>

CodeBehind

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

It doesn’t even give me a *required if I change the entire CodeBehind to this;

protected void ValidateStartTimeFun(object source, ServerValidateEventArgs args)
{
    args.isValid = false;
}

Answer 1

If you’re validating empty input, custom validators don’t fire if you set the ControlToValidate property AND don’t set the ValidateEmptyText property to true, otherwise the framework expects you to use a RequiredFieldValidator.

http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.customvalidator.validateemptytext.aspx