AJAX实现dropdownlis多级联动问题

各位大哥，我用asp.NET实现多级联动下拉框，设计页面代码如下，但是一直报错，错误为：
Microsoft JScript 运行时错误: Sys.WebForms.PageRequestManagerParserErrorException: 无法分析从服务器收到的消息。之所以出现此错误，常见的原因是: 在通过调用 Response.Write() 修改响应时，将启用响应筛选器、HttpModule 或服务器跟踪。
详细信息: 分析附近的“<STYLE>.ctl00_solpar”时出错。

代码贴出，求分析：



<%@ Page Language="C#" MasterPageFile="~/UTTCMasterPage.master" AutoEventWireup="true"

    CodeFile="Pro001_ProductQuery.aspx.cs" Inherits="Pro001_ProductQuery" Culture="auto"

    meta:resourcekey="PageResource1" UICulture="auto" %>



<asp:Content ID="HeadContent" ContentPlaceHolderID="HeadContent" runat="Server">



    <script type="text/JavaScript" language="javascript" src="App_Js/InputDate.js"></script>



    <style type="text/css">

        .style3

        {

            width: 200px;

        }

        .style4

        {

            width: 250px;

        }

    </style>



</asp:Content>

<asp:Content ID="pageContent" ContentPlaceHolderID="mainContent" runat="Server">

    <div class="tbTitile">

        <asp:Label ID="SearchText" runat="server"></asp:Label>

    </div>

    

    <asp:ScriptManager ID="ScriptManager2" runat="server">

    </asp:ScriptManager>

               <%--  <Triggers>

                <asp:PostBackTrigger   ControlID="ddlManufacturers" />

                <asp:PostBackTrigger  ControlID="ddlProductLine" />

                <asp:PostBackTrigger  ControlID="ddlCurrent_Inm" />

                <asp:PostBackTrigger  ControlID="ddlCurrent_In" />

                <asp:PostBackTrigger  ControlID="ddlAbilityLevel" />

                <asp:PostBackTrigger  ControlID="ddlControllerModel" />

                <asp:PostBackTrigger  ControlID="ddlSeries" />

                <asp:PostBackTrigger  ControlID="ddlInstallationStructure" />

                <asp:PostBackTrigger ControlID="btnSearch_S"  />

                

            </Triggers>--%>

     <asp:UpdatePanel ID="UpdatePanel2" runat="server">

            <ContentTemplate>

    <div class="tbContent">

        <table border="0" cellpadding="0" cellspacing="0" 

            style="width: 98%; margin-top: 10px;">

            <tr>

                <td class="style4" >

                    <asp:Label ID="lblManufacturers" runat="server" CssClass="inputlbl" Text=""></asp:Label><br />

                    <asp:DropDownList ID="ddlManufacturers" runat="server" CssClass="inputTextFir" 

                                AutoPostBack="True" 

                        onselectedindexchanged="ddlManufacturers_SelectedIndexChanged">

                            </asp:DropDownList>

                </td>

                <td class="style4" >

                   <asp:Label ID="lblProductLine" runat="server" CssClass="inputlbl" Text=""></asp:Label><br />

                    <asp:DropDownList ID="ddlProductLine" runat="server" CssClass="inputTextFir" 

                                AutoPostBack="True" TabIndex="1" 

                        onselectedindexchanged="ddlProductLine_SelectedIndexChanged"> </asp:DropDownList>

                </td>

                 <td class="style4" >

                   <asp:Label ID="lblCurrent_Inm" runat="server" CssClass="inputlbl" Text=""></asp:Label><br />

                    <asp:DropDownList ID="ddlCurrent_Inm" runat="server" CssClass="inputTextFir" 

                                AutoPostBack="True" TabIndex="2" 

                         onselectedindexchanged="ddlCurrent_Inm_SelectedIndexChanged"> </asp:DropDownList>

                </td>

                 <td >

                   <asp:Label ID="lblCurrent_In" runat="server" CssClass="inputlbl" Text=""></asp:Label><br />

                    <asp:DropDownList ID="ddlCurrent_In" runat="server" CssClass="inputTextFir" 

                                AutoPostBack="True" TabIndex="3" 

                         onselectedindexchanged="ddlCurrent_In_SelectedIndexChanged"> </asp:DropDownList>

                </td>

                

                 <td style="text-align:right" rowspan="2">

                 <br />

                    <asp:Button ID="btnSearch_S" runat="server" Text="" CssClass="btn" 

                         OnClick="btnSearch_S_Click" TabIndex="8" />

                </td>

            </tr>

            

            <tr>

                <td class="style4" >

                    <asp:Label ID="lblAbilityLevel" runat="server" CssClass="inputlbl" Text=""></asp:Label><br />

                    <asp:DropDownList ID="ddlAbilityLevel" runat="server" CssClass="inputTextFir" 

                                AutoPostBack="True" TabIndex="4" 

                        onselectedindexchanged="ddlAbilityLevel_SelectedIndexChanged">

                            </asp:DropDownList>

                </td>

                <td class="style4" >

                   <asp:Label ID="lblControllerModel" runat="server" CssClass="inputlbl" Text=""></asp:Label><br />

                    <asp:DropDownList ID="ddlControllerModel" runat="server" CssClass="inputTextFir" 

                                AutoPostBack="True" TabIndex="5" 

                        onselectedindexchanged="ddlControllerModel_SelectedIndexChanged"> </asp:DropDownList>

                </td>

                 <td class="style4" >

                   <asp:Label ID="lblSeries" runat="server" CssClass="inputlbl" Text=""></asp:Label><br />

                    <asp:DropDownList ID="ddlSeries" runat="server" CssClass="inputTextFir" 

                                AutoPostBack="True" TabIndex="6" 

                         onselectedindexchanged="ddlSeries_SelectedIndexChanged"> </asp:DropDownList>

                </td>

                 <td >

                   <asp:Label ID="lblInstallationStructure" runat="server" CssClass="inputlbl" Text=""></asp:Label><br />

                    <asp:DropDownList ID="ddlInstallationStructure" runat="server" CssClass="inputTextFir" 

                                AutoPostBack="True" TabIndex="7"> </asp:DropDownList>

                </td>

            </tr>

        </table>

    </div>

       </ContentTemplate>

            



            

        </asp:UpdatePanel>

    <div class="btnContent">

        <table border="0" cellpadding="0" cellspacing="0" style="width: 100%; margin-top: 10px;">

            <tr>

                <td style="width: 20%">

                </td>

                <td align="right">

  

                    <asp:Label ID="lblFileName" runat="server" CssClass="inputlbl"></asp:Label>

                    <asp:FileUpload ID="FileUpload" CssClass="fileupload" runat="server" />

                </td>

                <td align="right">

                    <asp:Button ID="btnImport" runat="server" Text="" CssClass="btn" 

                        onclick="btnImport_Click" />

                    <asp:Button ID="btnDelete" runat="server" Text="" CssClass="btn" />

                    <asp:Button ID="btnEdit_E" runat="server" Text="" CssClass="btn" 

                        onclick="btnEdit_E_Click"/>

                    <asp:Button ID="btnAdd_A" runat="server" Text="" CssClass="btn" 

                        onclick="btnAdd_A_Click" />

                </td>

            </tr>

        </table>

    </div>

    <div class="gvContent" style="height: 480px;">

        <asp:GridView ID="gvCustomerList" runat="server" CellPadding="0" CellSpacing="0"

            OnPageIndexChanging="gvCustomerList_PageIndexChanging" OnRowCommand="gvCustomerList_RowCommand"

            OnRowDataBound="gvCustomerList_RowDataBound"  OnSorting="gvCustomerList_Sorting">

            <FooterStyle CssClass="gvFooter" />

            <RowStyle CssClass="gvRow" />

            <EditRowStyle CssClass="gvEditRow" />

            <SelectedRowStyle CssClass="gvSelectedRow" />

            <PagerStyle CssClass="gvPager" />

            <HeaderStyle CssClass="gvHeader" Height="25px" HorizontalAlign="Center" />

            <AlternatingRowStyle CssClass="gvAlternatingRow" />

            <Columns>

                <asp:TemplateField HeaderText="Operation">

                    <ItemTemplate>

                        <asp:CheckBox ID="chkSelect" runat="server" CssClass="chkBox" Text=""/>

                    </ItemTemplate>

                </asp:TemplateField>

                <asp:TemplateField HeaderText="CustomerIDs" SortExpression="CustomerID">

                    <ItemTemplate>

                        <asp:LinkButton ID="lnkCustomerID" runat="server" Font-Underline="true"

                            CommandName="View"></asp:LinkButton>

                    </ItemTemplate>

                </asp:TemplateField>

            </Columns>

        </asp:GridView>

    </div>

    <div id="hidContent">

        <asp:HiddenField ID="hidRightString" runat="server" />

    </div>

</asp:Content>

ajax asp.net updatepanel --------------------编程问答-------------------- 如果不注释

<%--  <Triggers>                 <asp:PostBackTrigger   ControlID="ddlManufacturers" />                 <asp:PostBackTrigger  ControlID="ddlProductLine" />                 <asp:PostBackTrigger  ControlID="ddlCurrent_Inm" />                 <asp:PostBackTrigger  ControlID="ddlCurrent_In" />                 <asp:PostBackTrigger  ControlID="ddlAbilityLevel" />                 <asp:PostBackTrigger  ControlID="ddlControllerModel" />                 <asp:PostBackTrigger  ControlID="ddlSeries" />                 <asp:PostBackTrigger  ControlID="ddlInstallationStructure" />                 <asp:PostBackTrigger ControlID="btnSearch_S"  />                               </Triggers>--%>

则页面不联动更新，求怎么能让各个下拉框联动更新

--------------------编程问答-------------------- 1.引用必须的js或者jq过来.----不确定是不是需要,
2.看看你ajax返回的值是什么样的?
3.没有人知道你是如何将值绑定到ddl控件的.烦请贴代码 --------------------编程问答-------------------- 1.不太明白
2.怎么看ajax返回值
3.绑定ddl控件，第一个控件是Page_Load中绑定的，后面几个都是有前一个的selectchangge事件绑定，贴出第一个的：



 protected void ddlManufacturers_SelectedIndexChanged(object sender, EventArgs e)

    {

        string Manufacturers = this.ddlManufacturers.SelectedValue;

        string ManufacturersName = this.ddlManufacturers.SelectedItem.ToString();



        //获取检索条件

        ArrayList param = new ArrayList();

        param.Add(Manufacturers);

        DataTable dt = DbHelper.ExecuteCombine(pageId, SQL001, param);

        

        this.ddlProductLine.Items.Clear();

        this.ddlProductLine.Items.AddRange(f_GetListYuko(dt));

        //清空下拉框

        this.ddlCurrent_Inm.Items.Clear();

        this.ddlCurrent_In.Items.Clear();

        this.ddlAbilityLevel.Items.Clear();

        this.ddlControllerModel.Items.Clear();

        this.ddlSeries.Items.Clear();

        this.ddlInstallationStructure.Items.Clear();



    }

--------------------编程问答-------------------- 去掉ajax控件看看 --------------------编程问答-------------------- 去掉ajax控件，就不能局部刷新了，我就是要局部刷新才加的ajax --------------------编程问答-------------------- 用AJAX实现联动 --------------------编程问答-------------------- 我一开始就是用的ajax，把所有下拉框放入updatepanel中，但是这样只能用 <asp:PostBackTrigger ControlID="ddlManufacturers" /> 注册，不注册和注册异步那个都报错 --------------------编程问答-------------------- 我说的ajax不是.net封装的
自己手动写js后台取数据返回更新相应的select控件 --------------------编程问答-------------------- 你有几个ddl是联动的？ --------------------编程问答-------------------- 这代码，看的我纠结！！！！ --------------------编程问答-------------------- 7了下拉框联动 --------------------编程问答--------------------

引用 8 楼 DistantSola 的回复:

我说的ajax不是.net封装的
自己手动写js后台取数据返回更新相应的select控件

求指导-_- --------------------编程问答--------------------

引用 10 楼 hou306010849 的回复:

这代码，看的我纠结！！！！

求指教。。。。。。。。 --------------------编程问答-------------------- 建议LZ不要用ASP.NET控件了，自己用HTML+JS+Ashx 写一个就可以了，这东西网上源码太多了,样式你可以自己定义，效果一定会比ASP.NET控件方式做出来的好得多

补充：.NET技术 ,  ASP.NET