关于Ajax拓展控件CascadingDropDown级联下拉控件的问题

Question

using System;using System.Collections;using System.ComponentModel;using System.Data;using System.Linq;using System.Web;using System.Web.Services;using System.Web.Services.Protocols;using System.Xml.Linq;using AjaxControlToolkit;using System.Collections.Generic;using System.Data.SqlClient;using System.Collections.Specialized;namespace Ajax扩展控件{ /// <summary> /// MyCascadingWebService 的摘要说明 /// </summary> [WebService(Namespace = "http://tempuri.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] [ToolboxItem(false)] // 若要允许使用 ASP.NET AJAX 从脚本中调用此 Web 服务，请取消对下行的注释。 [System.Web.Script.Services.ScriptService] public class MyCascadingWebService : System.Web.Services.WebService { [WebMethod] public CascadingDropDownNameValue[] GetNewCate(string knownCategoryValues, string category) { List<CascadingDropDownNameValue> list = new List<CascadingDropDownNameValue>(); SqlConnection myCon = new SqlConnection(@"Data Source=.\SQLEXPRESS;Initial Catalog=newsystem;Integrated Security=True"); myCon.Open(); SqlCommand myCmd = new SqlCommand("select name,id from catepory", myCon); SqlDataReader myDR = myCmd.ExecuteReader(); while (myDR.Read()) { list.Add(new CascadingDropDownNameValue(myDR["name"].ToString(), myDR["id"].ToString())); } myCon.Close(); myDR.Close(); return list.ToArray(); } [WebMethod] public CascadingDropDownNameValue[] GetNewTitle(string knownCategoryValues, string category) { List<CascadingDropDownNameValue> list = new List<CascadingDropDownNameValue>(); StringDictionary sdc = AjaxControlToolkit.CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues); if (!sdc.ContainsKey("name")) { return null; } SqlConnection myCon = new SqlConnection(@"Data Source=.\SQLEXPRESS;Initial Catalog=newsystem;Integrated Security=True"); myCon.Open(); string cateid = sdc["name"]; SqlCommand myCmd = new SqlCommand("select title,id from news where cateid=@cateid", myCon); myCmd.Parameters.AddWithValue("@cateid", cateid); SqlDataReader myDR = myCmd.ExecuteReader(); while (myDR.Read()) { list.Add(new CascadingDropDownNameValue(myDR["title"].ToString(), myDR["id"].ToString())); } myCon.Close(); myDR.Close(); return list.ToArray(); } }}   <asp:ScriptManager ID="ScriptManager1" runat="server" EnableScriptGlobalization="true" EnableScriptLocalization="true"> </asp:ScriptManager> <table style="width: 100%;"> <tr> <td>新闻类别:</td> <td> <asp:DropDownList ID="DropDownList1" runat="server"> </asp:DropDownList> <ajax:CascadingDropDown ID="DropDownList1_CascadingDropDown" runat="server" Enabled="True" TargetControlID="DropDownList1" Category="category" PromptText="请选择一个新闻类别" LoadingText="载入中..." ScriptPath="MyCascadingWebService.asmx" ServiceMethod="GetNewCate"> </ajax:CascadingDropDown> </td> </tr> <tr> <td>新闻标题:</td> <td> <asp:DropDownList ID="DropDownList2" runat="server"> </asp:DropDownList> <ajax:CascadingDropDown ID="DropDownList2_CascadingDropDown" runat="server" Enabled="True" TargetControlID="DropDownList2" Category="title" PromptText="请选择一个新闻标题" LoadingText="载入中..." ScriptPath="MyCascadingWebService.asmx" ServiceMethod="GetNewTitle" ParentControlID="DropDownList1"> </ajax:CascadingDropDown> </td> </tr> </table>   运行时出错提示:1.Uncaught syntaxError:Unexpected token < 说是MyCascadingWebService.asmx 3行 字符1 有语法错误2.Sys.ArgumentUndefinedException:值不能是未定义的。参数名:type 是出自ScriptResource.axd?d=*****&t=******

Answer 1

卡断点调试、看sql语句执行查询到没有、在就是看控件设定是不是正确