C# OnCheckedChanged() Method not working in Repeater, I want to get VALUE from Particulate Item In Repeater

I have an two Repeater control Outer and Inner, I want to access value from Inner Repeater on code behind.

Sample code:

<asp:Repeater ID="Repeater1" runat="server" OnItemDataBound="Repeater1_ItemDataBound">
       <HeaderTemplate>
               <div class="tab-content">
                </HeaderTemplate>
                                <ItemTemplate>
                                       <div class="tab-pane" id='<%# Eval("href_li")%>'>
                                             <asp:HiddenField ID="CustId1" Value='<%# Eval("Id")%>' runat="server" />
                                                        <asp:Repeater ID="RptTopic" OnItemDataBound="RptTopic_ItemDataBound" OnItemCommand="RptTopic_ItemCommand" OnItemCreated="RptTopic_ItemCreated" runat="server">
                                                             <ItemTemplate>
                                                                  <div class="row">
                                                                     <div class="span1">
                                                                          <asp:HiddenField ID="IsDef" Value='<%# Eval("IsDeafult") %>' runat="server" />
                                                                          <asp:HiddenField ID="CustId" Value='<%# Eval("Custid")%>' runat="server" />
                                                                    </div>
                                                                      <div class="span1">
                                                                          <asp:CheckBox ID="custChkbx" OnCheckedChanged="custChkbx_CheckedChanged1"    Visible="false" runat="server" />
                                                                      </div>
                                                                    <asp:Label ID="CustTopic" runat="server" Text='<%# Eval("Disc") %>'></asp:Label>
                                                                   <asp:Label ID="lblprice" runat="server" Text='<%# Eval("Price") %>'></asp:Label>
                                                            </ItemTemplate>
                                                        </asp:Repeater>
                                                    </div>
                             </ItemTemplate>
                     </asp:Repeater>

from this I want to access a VALUE of ' lblprice ' in code behind when 'custChkbx' Checked or Unchecked. Thank You !!!