Validate CheckBoxList on the registration page

Question

Hi!

This code:

Imports Microsoft.VisualBasic
Namespace CustomListValidator
    ''' <summary>
    ''' Summary description for ListValidator
    ''' </summary>

    Public Class ListValidator
        Inherits BaseValidator
        Public Sub New()

        End Sub

        Protected Overrides Function ControlPropertiesValid() As Boolean
            Dim ctrl As Control = TryCast(FindControl(ControlToValidate), ListControl)
            Return (Not ctrl Is Nothing)
        End Function

        Protected Overrides Function EvaluateIsValid() As Boolean
            Return Me.CheckIfItemsIsChecked()
        End Function

        Protected Function CheckIfItemsIsChecked() As Boolean
            Dim listItemValidate As ListControl = (CType(Me.FindControl(Me.ControlToValidate), ListControl))
            For Each listItem As ListItem In listItemValidate.Items
                If listItem.Selected = True Then
                    Return True
                End If
            Next listItem
            Return False
        End Function
    End Class
End Namespace

designed to validate CheckBoxList control, works on the ordinary pages, but does not work on the registration page.

Here is my registration page:

                               

<%@ Page Title="Register" Language="VB" MasterPageFile="~/Site.Master" AutoEventWireup="false"
    CodeFile="Register.aspx.vb" Inherits="Account_Register" %>
    <%@ Register TagPrefix="CLV" Namespace="CustomListValidator" %>
<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
</asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
    <asp:CreateUserWizard ID="RegisterUser" runat="server" EnableViewState="false">
        <LayoutTemplate>
            <asp:PlaceHolder ID="wizardStepPlaceholder" runat="server"></asp:PlaceHolder>
            <asp:PlaceHolder ID="navigationPlaceholder" runat="server"></asp:PlaceHolder>
        </LayoutTemplate>
        <WizardSteps>
            <asp:CreateUserWizardStep ID="RegisterUserWizardStep" runat="server">
                <ContentTemplate>
                    <h2>
                        Create a New Account
                    </h2>
                    <p>
                        Use the form below to create a new account.<br />
                        Passwords are required to be a minimum of <%= Membership.MinRequiredPasswordLength %> characters in length.
                    </p>
                    <%--<span class="failureNotification">
                        <asp:Literal ID="ErrorMessage" runat="server"></asp:Literal>
                    </span>
                    <asp:ValidationSummary ID="RegisterUserValidationSummary" runat="server" CssClass="failureNotification" 
                         ValidationGroup="RegisterUserValidationGroup"/>--%>


                    <div class="accountInfo">
                        <fieldset class="register">
                            <legend>Account Information</legend>

<%--Here are the usual fields--%>

                            

                            <br />
                                <asp:Label ID="LabLanguage" runat="server"></asp:Label><br />
                                <CLV:ListValidator ID="custLstVal" ControlToValidate="UserLanguage" Display="Dynamic"
                            ErrorMessage="At least one item in the checkboxlist chould be checked" ValidationGroup="RegisterUserValidationGroup" 
                            runat="server" ToolTip="At least one item in the checkboxlist chould be checked"></CLV:ListValidator>

                                <asp:CheckBoxList ID="UserLanguage" RepeatColumns="4" RepeatLayout="Table" 
                                RepeatDirection="Horizontal" runat="server" AppendDataBoundItems="False" AutoPostBack="False" CausesValidation="False">
                                    <asp:ListItem Value="ar">Arabic</asp:ListItem>
                                    <asp:ListItem Value="bg">Bulgarian</asp:ListItem>
                                    <asp:ListItem Value="ca">Catalan</asp:ListItem>
                                    <asp:ListItem Value="zh-CHS">Chinese (Simplified)</asp:ListItem>
                                    <asp:ListItem Value="zh-CHT">Chinese (Traditional)</asp:ListItem>
                                    <asp:ListItem Value="cs">Czech</asp:ListItem>
                                    <asp:ListItem Value="da">Danish</asp:ListItem>
                                    <asp:ListItem Value="nl">Dutch</asp:ListItem>
                                    <asp:ListItem Value="en">English</asp:ListItem>
                                    <asp:ListItem Value="et">Estonian</asp:ListItem>
                                    <asp:ListItem Value="fi">Finnish</asp:ListItem>
                                    <asp:ListItem Value="fr">French</asp:ListItem>
                                    <asp:ListItem Value="de">German</asp:ListItem>
                                    <asp:ListItem Value="el">Greek</asp:ListItem>
                                    <asp:ListItem Value="ht">Haitian Creole</asp:ListItem>
                                    <asp:ListItem Value="he">Hebrew</asp:ListItem>
                                    <asp:ListItem Value="hi">Hindi</asp:ListItem>
                                    <asp:ListItem Value="hu">Hungarian</asp:ListItem>
                                    <asp:ListItem Value="id">Indonesian</asp:ListItem>
                                    <asp:ListItem Value="it">Italian</asp:ListItem>
                                    <asp:ListItem Value="ja">Japanese</asp:ListItem>
                                    <asp:ListItem Value="ko">Korean</asp:ListItem>
                                    <asp:ListItem Value="lv">Latvian</asp:ListItem>
                                    <asp:ListItem Value="lt">Lithuanian</asp:ListItem>
                                    <asp:ListItem Value="mww">Hmong Daw</asp:ListItem>
                                    <asp:ListItem Value="no">Norwegian</asp:ListItem>
                                    <asp:ListItem Value="pl">Polish</asp:ListItem>
                                    <asp:ListItem Value="pt">Portuguese</asp:ListItem>
                                    <asp:ListItem Value="ro">Romanian</asp:ListItem>
                                    <asp:ListItem Value="ru">Russian</asp:ListItem>
                                    <asp:ListItem Value="sk">Slovak</asp:ListItem>
                                    <asp:ListItem Value="sl">Slovenian</asp:ListItem>
                                    <asp:ListItem Value="es">Spanish</asp:ListItem>
                                    <asp:ListItem Value="sv">Swedish</asp:ListItem>
                                    <asp:ListItem Value="th">Thai</asp:ListItem>
                                    <asp:ListItem Value="tr">Turkish</asp:ListItem>
                                    <asp:ListItem Value="uk">Ukrainian</asp:ListItem>
                                    <asp:ListItem Value="vi">Vietnamese</asp:ListItem>
                                </asp:CheckBoxList>
                        </fieldset>
                        <p class="submitButton">
                            <asp:Button ID="CreateUserButton" runat="server" CommandName="MoveNext" Text="Create User" 
                                 ValidationGroup="RegisterUserValidationGroup"/>
                        </p>
                    </div>
                </ContentTemplate>
                <CustomNavigationTemplate>
                </CustomNavigationTemplate>
            </asp:CreateUserWizardStep>
        </WizardSteps>
    </asp:CreateUserWizard>
</asp:Content>

Please tell me, what I need to change in the code.