AutoComplete模糊查询匹配关联控件的问题

一个页面上有两个TextBox框,分别是任务编号TextBox和任务名称TextBox
数据库表tableC
Id  OrderNo(任务编号)   OrderName(任务名称)
1   201310120001       任务名称1
2   201310120002       任务名称2

前台页面:

<asp:ScriptManager ID="ScriptManager1" runat="server">

                                                                                        </asp:ScriptManager>

                                                                                        <div>

        //任务编号TextBox                                                                                    <asp:TextBox ID="txt_OrderNo" runat="server" autocomplete="off" Width="300"></asp:TextBox>

                                                                                            <cc1:AutoCompleteExtender ID="autoComplete1" runat="server" CompletionInterval="1000"

                                                                                                CompletionSetCount="12" EnableCaching="true" MinimumPrefixLength="0" ServiceMethod="GetList"