<asp:DataList ID="dtQuestion" runat="server" RepeatDirection="Vertical" OnItemDataBound="FormatDataListRow" >
        <ItemTemplate>
            <asp:Panel id="panel" runat="server" BorderColor="#536895" BorderStyle="Solid" BorderWidth="1" style="display: none;" EnableViewState="true">
                <asp:Label id="lblQuestionDesc" runat="server" Text="" ></asp:Label>
                <asp:RadioButtonList id="rbl" runat="server" EnableViewState="true" >    </asp:RadioButtonList>
                </asp:Panel>
            </ItemTemplate>
</asp:DataList>

string id;
       if     (c.GetType().ToString().Equals("System.Web.UI.WebControls.RadioButtonList"))
               {
                   if (c.ID != "rbl")
                   {
                    id = c.ID;
                    al.Add(id + "," + ((RadioButtonList)c).SelectedItem.Value); //SelectedValue);  //
                }
            }