控件包含代码块(即 )，因此无法修改控件集合

各位，我编程出现以下问题，请问市什么问题
Page_Error
控件包含代码块(即 )，因此无法修改控件集合。
 Application Error 在 System.Web.UI.PageTheme.SetStyleSheet() 在 System.Web.UI.Page.OnInit(EventArgs e) 在 System.Web.UI.Control.InitRecursive(Control namingContainer) 在 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
具体代码如下：
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="WebMapApp._Default" %><%@ Register Src="Measure.ascx" TagName="Measure" TagPrefix="uc2" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html id="Html1" runat="server" xmlns="http://www.w3.org/1999/xhtml" dir="ltr">
<head id="Head1" runat="server">
    <title>智能交通控制中心</title>
 
    <script  language="javascript" type="text/javascript">
        function GetResourceContent()
        {
            var message = 'ActiveType=GetResourceContent';
            var context = 'Page1';
            <%=getResourceContentCallBack%>    
        }
        
       
        
        function AttributeQuery()
        {
            var layer = document.getElementById("LayerList");
            var condition = document.getElementById("queryCondition");
            var message = 'ActiveType=AttributeQuery&EventArg=';
            message += layer.value;
            message += "&Condtion=" + condition.value;
            var context = 'Page1';
            <%=attributeQueryCallBack%>
        }
    </script>
    
    <%--  For LTR. . . use these styles if dir="ltr" in html tag    --%>
    <style type="text/css">
        .appFloat1 {float: left;} 
        .appFloat2 {float: right;} 
        .appAlign1 {text-align: left;} 
        .appAlign2 {text-align: right;} 
        .combined1 {float: left; text-align: left;}
        .combined2 {float: right; text-align: right;}
        .mapPosition {left: 260px; visibility: visible;} 
        .dockPosition {left: 0px; visibility: visible;} 
        .dockToggleClass {visibility: visible;}
        .offview {top: 1600px;}
        #Query
        {
            width: 71px;
            top: 557px;
            left: 42px;
        }
        #queryCondition
        {
            width: 173px;
            height: 43px;
        }
    </style>
    <%--  For RTL. . . use these styles if dir="rtl" in html tag
    <style type="text/css">
        .appFloat1 {float: right;} 
        .appFloat2 {float: left;} 
        .appAlign1 {text-align: right;} 
        .appAlign2 {text-align: left;} 
        .combined1 {float: right; text-align: right;}
        .combined2 {float: left; text-align: left;}
        .mapPosition {left: 0px; visibility: hidden;} 
        .dockPosition {left: 512px; visibility: hidden;} 
        .dockToggleClass {visibility: hidden;}
        .offview {top: 1600px;}
    </style>    --%>
</head>
<body style="margin: 0px 0px 0px 0px; background-color: white; width: 100%; font-family: Verdana;
    font-size: 8pt;">
    <form id="form1" runat="server">
    <asp:ScriptManager ID="ScriptManager1" runat="server" EnablePageMethods="true" EnableScriptGlobalization="True" />
    <%-- Page Header --%>
    <asp:Panel runat="server" ID="PageHeader" CssClass="MapViewer_TitleBannerStyle" Width="100%"
        Height="50px" Style="position: relative;">
        <div id="TitleMenuDiv" style="top: 0px;">
            <div class="appFloat1" style="padding: 15px 5px 0px 5px">
                <asp:Label ID="PageTitle" runat="server" Text="智能交通控制中心" Font-Size="12pt"
                    Font-Names="Verdana" ForeColor="White" Font-Bold="True" Style="z-index: 100;"></asp:Label>
            </div>
            <div class="combined2">
                <asp:Menu ID="TitleMenu" runat="server" SkipLinkText="" BackColor="Transparent" Orientation="Horizontal"
                    Font-Size="8pt">
                   <Items>
                        <asp:MenuItem NavigateUrl="http://www.fsjtw.gov.cn/" SeparatorImageUrl="~/images/separator.gif"
                            Target="_Blank" Text="佛山市交通运输局" Value="佛山市交通运输局"></asp:MenuItem>
                        <asp:MenuItem NavigateUrl="http://jtj.chancheng.gov.cn/" SeparatorImageUrl="~/images/separator.gif"
                            Target="_Blank" Text="禅城交通公共网" Value="禅城交通公众网"></asp:MenuItem>
                        <asp:MenuItem NavigateUrl="Help/Default.htm" Target="_Blank" Text="Help" Value="Help">
                        </asp:MenuItem>
                    </Items>
                </asp:Menu>
                <asp:LoginName ID="LoginName1" runat="server" ForeColor="White" Font-Size="8pt" FormatString="Logged in as {0}" />
                &nbsp;&nbsp;
                <asp:LoginStatus ID="LoginStatus1" runat="server" Font-Size="8pt" ForeColor="White"
                    LogoutAction="RedirectToLoginPage" Style="text-decoration: none" onmousedown="LogOut()"
                    onmouseover="this.style.color='Black'" onmouseout="this.style.color='White'" />
                &nbsp;&nbsp;
                <asp:HyperLink ID="CloseHyperLink" runat="server" Style="color: White; font-family: Verdana; font-size: 8pt; text-decoration: none;"
                    NavigateUrl="JavaScript: CloseOut()" Visible="False"
                    ToolTip="Close Application" onmouseover="this.style.color='Black'" onmouseout="this.style.color='White'">Close&nbsp;&nbsp;</asp:HyperLink>
            </div>
        </div>
    </asp:Panel>