Need Help NavigateUrl with a Dynamic Value

Hello All,
In a .NET C# WebForm I'm looping each cms_mastermenu Object to display data.
BUT I need to set a link to edit each item
If i Write NavigateUrl="~/Admin/gestionmenu.aspx?<%=tempstr%>"
It does not work the result give me http://localhost:81/Admin/gestionmenu.aspx?<%=tempstr%>
CAN SOMEONE HELP ME TO SET THE NavigateUrl with a Dynamic Value ?
Thanks
<%
    foreach (cms_mastermenu MenuListItem in MasterMenuList)
    {
        tempstr = MenuListItem.id.ToString();
        %>
        <div class="rowdiv">
            <div  class="celldiv" style="width:33%"><%=tempstr%></div>
            <div  cla ...