Custom Validator to validate at-least one CheckBox checked inside ASP.Net ListView using JavaScript

Hi nauna,

Refer below sample.

HTML

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script type="text/javascript">
    function ValidateCheckBoxList1(sender, args) {
        var checkBoxList = $("#post").find($("[id*=chkGender] input"));
        var isValid = false;
        for (var i = 0; i < checkBoxList.length; i++) {
            if (checkBoxList[i].checked) {
                isValid = true;
                break;
            }
        }
        args.IsValid = isValid;
    }
</script>
<div>
    <asp:ListView runat="server" ID="ListView1">
        <ItemTemplate>
            <div id="post">
                <asp:Label Text='<%#Eval("Id") %>' runat="server" />
                <asp:CheckBoxList ID="chkGender" runat="server" RepeatDirection="Horizontal">
                    <asp:ListItem Text="Male" Value="M" />
                    <asp:ListItem Text="Female" Value="F" />
                </asp:CheckBoxList>
                <asp:CustomValidator ID="cust" runat="server" ClientValidationFunction="ValidateCheckBoxList1"
                    ErrorMessage="Please select checkBoxList" ForeColor="Red" ValidationGroup="p1"></asp:CustomValidator>
            </div>
        </ItemTemplate>
    </asp:ListView>
    <asp:Button Text="Submit" runat="server" ValidationGroup="p1" />
</div>

Namespaces

C#

using System.Data;

VB.Net

Imports System.Data

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.Add("Id");
        dt.Rows.Add(1);
        dt.Rows.Add(2);
        dt.Rows.Add(3);
        dt.Rows.Add(4);
        this.ListView1.DataSource = dt;
        ListView1.DataBind();
    }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim dt As DataTable = New DataTable()
        dt.Columns.Add("Id")
        dt.Rows.Add(1)
        dt.Rows.Add(2)
        dt.Rows.Add(3)
        dt.Rows.Add(4)
        Me.ListView1.DataSource = dt
        ListView1.DataBind()
    End If
End Sub

Screenshot