How can we find child repeater control

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ASP.NET

C#3.5

<pre> <asp:Repeater ID="rptMenu" runat="server" OnItemDataBound="rptMenu_OnItemBound">
        <ItemTemplate>
            <li id="lst" runat="server" class="accordion-group">
                <div class="accordion-heading">
                <a runat="server" id="menuItemlnk" href='#<%#Eval("MenuID") %>' data-parent="#mainSideMenu" data-toggle="collapse" class="accordion-toggle"><span class="item-icon aweso-icon-list-alt"></span><%#Eval("MenuName") %></a>
                </div>
                <ul class="menu" id='<%#Eval("MenuID") %>'>
                    <asp:Repeater ID="rptChildMenu" runat="server">
                        <ItemTemplate>
                    <li class="active"><a runat="server" id="MenuchildItemLnk" href='<%#Eval("URL") %>'>^__i class="fontello-icon-right-dir"><%#Eval("MenuName") %></a></li>
                        </ItemTemplate>
                    </asp:Repeater>
                </ul>
            </li>
            <!-- // item accordionMenu Calendar -->
        </ItemTemplate>
    </asp:Repeater>

how can we find the control MenuchildItemLnk of repeater rptChildMenu?

What I have tried:

i tried to get through this code but error

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        Repeater rpt = (Repeater)Page.Master.FindControl("rptMenu");
        Repeater Childrpt = (Repeater)rpt.FindControl("rptChildMenu");

        if (Childrpt != null)
        {
            foreach(RepeaterItem item in rpt.Items)
            {
                if(item.ItemType==ListItemType.Item || item.ItemType == ListItemType.AlternatingItem)
                {

                    HtmlAnchor Lnk = (HtmlAnchor)item.FindControl("MenuchildItemLnk");

                    if (Lnk.HRef == "frmExpenseCode.aspx")
                    {
                        string UID = Session["UID"].ToString();

                        string expCode = GetExpCode(UID);
                        txtEcode.Text = expCode;
                    }

                }
            }

        }


    }

}