ScriptManager中UpdatePanel嵌套UpdatePanel[局部刷新]

//前台代码
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="ProductEdit.ascx.cs"
    Inherits="Unisoft.ICS.Web.Stock.UserControls.ProductEdit" %>
 <%@ Register Src="~/UserControls/Common/ProductType.ascx" TagName="ProductType" TagPrefix="uc" %>
 <%@ Register Src="~/Stock/UserControls/NavigationBar.ascx" TagName="NavigationBar"
     TagPrefix="uc" %>
 <%@ Register Src="~/UserControls/Common/DisplayPicture.ascx" TagName="DisplayPicture"
     TagPrefix="uc" %>
 <%@ Register Src="~/UserControls/Common/PopupLoader.ascx" TagName="PopupLoader" TagPrefix="uc" %>
 <uc:ProductType ID="ucProductType" runat="server" />
 <div id="locality">
     <uc:NavigationBar ID="ucNavigationBar" runat="server" />
 </div>
 <div class="inner">
     <asp:UpdatePanel ID="uppProduct" runat="server" UpdateMode="Conditional">
         <ContentTemplate>
             <p class="note" id="lblNote" runat="server">
                 新添加的物资缺省允许被预订，如需改变，请到“系统管理-->主页管理-->供应产品”中操作“主页被检索”选项！！</p>
             <p class="note" id="P1" runat="server">
                 新添加的物资缺省允许库存和销量推送，如需改变，请到“档案编缉”中操作相应选项！！</p>
             <table class="tblRidge">
                 <tr>
                     <th>
                         <span class="required">*</span>物资名称：
                     </th>
                     <td colspan="3">
                         <asp:TextBox ID="txtProductName" runat="server" CssClass="txt tInput"></asp:TextBox>
                         <p class="errorMsg">
                             <asp:RequiredFieldValidator ID="rfvProductName" runat="server" ControlToValidate="txtProductName"
                                 Display="Dynamic" CssClass="error" ValidationGroup="vgSubmit"></asp:RequiredFieldValidator></p>
                     </td>
                 </tr>
             </table>
             <asp:UpdatePanel ID="up" runat="server" UpdateMode="Conditional">
                 <ContentTemplate>
                     <table class="tblRidge">
                         <%--<tr>
                             <th width="100%">
                             </th>
                             <td colspan="3">
                                 <font color="blue">只有选择的分类配置了扩展属性才允许编辑此部份数据，配置请到“系统管理-->参数管理-->库存管理-->物资扩展属性管理”进行</font>
                             </td>
                         </tr>--%>
                         <tr>
                             <th>
                                 <asp:Label ID="lbl_add1" runat="server" Text="扩展属性1" ForeColor="Orange" ToolTip="所选择的分类在系统管理中配置后在此可编缉"></asp:Label>
                             </th>
                             <td width="40%">
                                 <asp:TextBox ID="add1" runat="server" CssClass="txt" Enabled="false"></asp:TextBox>
                             </td>
                             <th>
                                 <asp:Label ID="lbl_add2" runat="server" Text="扩展属性2" ForeColor="Orange" ToolTip="所选择的分类在系统管理中配置后在此可编缉"></asp:Label>
                             </th>
                             <td >
                                 <asp:TextBox ID="add2" runat="server" CssClass="txt" Enabled="false"></asp:TextBox>
                             </td>
                         </tr>
                     </table>
                     <asp:Button ID="btnUp" runat="server" OnClick="btnUp_Click" Style="display: none;" />
                 </ContentTemplate>
             </asp:UpdatePanel>
             <table class="tblRidge">
                 <div id="if_show" runat="server" visible="false">
                     <tr id="pnlIsRecommend" runat="server" visible="false">
                         <th>
                             是否推荐：
                         </th>
                         <td>
                             <asp:CheckBox ID="chkbIsRecommend" runat="server" Text="勾选则在主页中推荐" />
                         </td>
                     </tr>
                 </div>
                 <tr>
             </table>
             <p class="tCt ">
                 <asp:Button ID="btnSubmit" runat="server" CssClass="rbtn23" Text="添加" OnClick="btnSubmit_Click"
                     ValidationGroup="vgSubmit" />
                 <asp:Button ID="btnBack" runat="server" CssClass="rbtn23" Text="返回" OnClick="btnBack_Click" />
                 <asp:HiddenField ID="txtProductID" Value="-1" runat="server" />
                 <asp:HiddenField ID="hidReturnURL" runat="server" />
             </p>
         </ContentTemplate>
     </asp:UpdatePanel>
     <asp:Button ID="btnSetlbtxt" runat="server" Visible="false" Text="Button" OnClick="btnSetlbtxt_Click" />
 </div> 
//后台方法
 protected void chk_kzinfo()
{
    this.lbl_add1.Text = "扩展属性1";
                   this.add1.Enabled = false;
                   this.add1.Text = "";
                   this.lbl_add1.ForeColor = System.Drawing.Color.Orange;
                
                   this.lbl_add2.Text = "扩展属性2";
                   this.add2.Enabled = false;
                   this.add2.Text = "";
                   this.lbl_add2.ForeColor = System.Drawing.Color.Orange;

 }