Gridview update using usercontrol
                            
                         
                        
                     
                 
                
                    when i click on update using edit button in gridview. usercontrol is not getting popup here is my code. 
 <%@ Page Title="" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="GridUser.aspx.cs" Inherits="aspprojects2.Gridview.GridUser" %>
 
 <%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %>
 <%@ Register Src="~/usercontrol/LocationUser.ascx" TagName="usercontrol" TagPrefix="uc1"%>
 <asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" runat="server">
 </asp:Content>
 <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
   <asp:ScriptManager ID="scm" runat="server"></asp:ScriptManager>
 <asp:UpdatePanel ID="up1" runat="server">
   <ContentTemplate>
   <asp:GridView ID="gv" runat="server" AutoGenerateColumns="false" DataKeyNames="locationid">
   <Columns>
   <asp:TemplateField HeaderText="LocationId">
   <ItemTemplate>
   <asp:Label ID="lbllocationid" runat="server" Text='<%# Eval("locationid") %>'></asp:Label>
   </ItemTemplate>
   </asp:TemplateField>
   <asp:TemplateField HeaderText="Regionalgroup">
   <ItemTemplate>
   <%# Eval("regionalgroup") %>
   </ItemTemplate>
   <EditItemTemplate>
   <asp:TextBox ID="txtregionalgroup" runat="server" Text='<%# Eval("regionalgroup") %>'></asp:TextBox>
   </EditItemTemplate>
   </asp:TemplateField>
   <asp:TemplateField>
   <ItemTemplate>
   <asp:LinkButton ID="lnkedit" runat="server" Text="Edit" OnClick="Edit"></asp:LinkButton>
   </ItemTemplate>
   </asp:TemplateField>
   </Columns>
   </asp:GridView>
 
   <asp:LinkButton ID="lnkfake" runat="server"></asp:LinkButton>
   <uc1:usercontrol id="uc" runat="server" EnableViewState="false" style="display:none">
   </uc1:usercontrol>
 
   <asp:ModalPopupExtender ID="ModalPopupExtender1" runat="server" PopupControlID="uc"
   TargetControlID="lnkfake" BackgroundCssClass="modalBackground" 
   DropShadow="false">
   </asp:ModalPopupExtender>
    
   </ContentTemplate>
   <Triggers>
   <asp:AsyncPostBackTrigger ControlID="gv" />
    
   </Triggers>
 </asp:UpdatePanel>
 </asp:Content>
 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;
 using System.Web.UI;
 using System.Web.UI.WebControls;
 using DAL;
 using BO;
 
 namespace aspprojects2.Gridview
 {
   public partial class GridUser : System.Web.UI.Page
   {
   Employees emp = new Employees();
   protected void Page_Load(object sender, EventArgs e)
   {
   if (!IsPostBack)
   FillLocations();
   }
 
   protected void FillLocations()
   {
   gv.DataSource = emp.GetLocations();
   gv.DataBind();
   }
 
   protected void Edit(object sender, EventArgs e)
   {
   LinkButton lnk = sender as LinkButton;
   GridViewRow row = (GridViewRow)lnk.NamingContainer;
   uc.locationid = Convert.ToInt32( gv.DataKeys[row.RowIndex].Value.ToString());
   uc.regionalgroup = row.Cells[1].ToString();
   ModalPopupExtender1.Show();
   }
   }
 }
 .ascx
 <%@ Control Language="C#" AutoEventWireup="true" CodeBehind="LocationUser.ascx.cs" Inherits="aspprojects2.LocationUser" %>
 <asp:UpdatePanel ID="up2" runat="server">
 <ContentTemplate>
 <asp:Panel ID="pnl" runat="server" CssClass="modalPopup" >
 <table>
   <tr>
   <td>
   <asp:Label ID="lbllocationid" runat="server" Text="LocationId"></asp:Label>
   </td>
   <td>
   <asp:TextBox ID="txtlocationid" runat="server"></asp:TextBox>
   </td>
   </tr>
   <tr>
   <td>
   <asp:Label ID="lblregionalgroup" runat="server" Text="RegionalGroup"></asp:Label>
   </td>
   <td>
   <asp:TextBox ID="txtregionalgroup" runat="server"></asp:TextBox>
   </td>
   </tr>
   <tr>
   <td>
   <asp:Button ID="btnsave" runat="server" Text="Save" onclick="btnsave_Click" />
   </td>
   <td>
   <asp:Button ID="btncancel" runat="server" Text="Cancel" />
   </td>
   </tr>
 
 </table>
 </asp:Panel>
 </ContentTemplate>
 </asp:UpdatePanel>
 
 .ascx.cs
 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;
 using System.Web.UI;
 using System.Web.UI.WebControls;
 using DAL;
 using BO;
 
 namespace aspprojects2
 {
   public partial class LocationUser : System.Web.UI.UserControl
   {
 
   private int _locatonid = 0;
   private string _regionalgroup = string.Empty;
 
   #region properties
   public int locationid
   {
   get { return _locatonid; }
   set { _locatonid = value; }
   }
 
   public string regionalgroup
   {
   get { return _regionalgroup; }
   set { _regionalgroup = value; }
   }
   #endregion properties
 
   Employees emp = new Employees();
   Location lo = new Location();
   protected void Page_Load(object sender, EventArgs e)
   {
   if (!IsPostBack)
   txtlocationid.Text = locationid.ToString();
   txtregionalgroup.Text = regionalgroup;
   }
 
   protected void btnsave_Click(object sender, EventArgs e)
   {
   lo.locationid = Convert.ToInt32(txtlocationid.Text);
   lo.regionalgroup = txtregionalgroup.Text;
   emp.updatelocation(lo);
   }
   }
 }
 i am getting error like this.
 Microsoft JScript runtime error: 'this._foregroundElement.parentNode' is null or not an object