ajax控制工具包cascadingdropdown Web服务错误C＃

Question

I am trying to use the ajax control toolkit cascadingdropdown with a web service but I keep getting "Method Error 0" in the initial drop down box when using web service. If I tried not using web service on initial drop down I got the same error on the second (cascading drop down).

Here is my code for the web service and the drop downs:

     <asp:DropDownList ID="ServerDropDown" runat="server"></asp:DropDownList>

    <ajaxToolkit:CascadingDropDown
        ID="CascadingDropDown2"
        runat="server"
        TargetControlID="ServerDropDown" 
        Category="ServerID" 
        PromptText="-- Select one --"                         
        ServiceMethod="GetServerValues"
        ServicePath="../App_Data/Search.asmx.cs"
         />


    <asp:DropDownList ID="DatabaseDropDown" runat="server"></asp:DropDownList>

    <ajaxToolkit:CascadingDropDown
        ID="CascadingDropDown1"
        runat="server"
        TargetControlID="DatabaseDropDown" 
        ParentControlID="ServerDropDown"
        Category="DatabaseID" 
        PromptText="-- Select one --"             
        ServiceMethod="GetDatabasesForServer"
        ServicePath="../App_Data/Search.asmx.cs"
         />

service code:

using System;
using System.Web;
using System.Web.Services;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using AjaxControlToolkit;
using System.Collections.Generic;

///<summary>
/// Summary description for ServiceCS
///</summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[System.Web.Script.Services.ScriptService]


public class Search : System.Web.Services.WebService
{

    [System.Web.Services.WebMethod]
    [System.Web.Script.Services.ScriptMethod]    
    public CascadingDropDownNameValue[] GetDatabasesForServer(string knownCategoryValues, string category)
    {
        //StringDictionary kv = CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues);

        //int ServerID;
        //if (!kv.ContainsKey("Server") || !Int32.TryParse(kv["Server"], out ServerID))
        //{
        //    return null;
        //}

        string ServerID = CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues)["ServerID"];

        string sSQL = @"SELECT DL.DatabaseID AS value, SL.ServerName + ' - ' + DL.DatabaseName AS DisplayText " +
                "FROM BabelFish.dbo.DatabaseList DL (NOLOCK) " +
                "INNER JOIN BabelFish.dbo.ServerList SL (NOLOCK) ON DL.ServerId = SL.ServerId " +
                "WHERE DL.IsActive = 1 " +
                "AND SL.ServerID = '" + ServerID + "' " +
                "Order by DisplayText";

        DataTable dt = DatabaseAccessing.DatabaseConnection.GetDataTable(sSQL);

        List<CascadingDropDownNameValue> values = new List<CascadingDropDownNameValue>();

        for (int i = 0; i < dt.Rows.Count; i++)
        {
            DataRow dr = dt.Rows[i];
            values.Add(new CascadingDropDownNameValue((string)dr["DisplayText"], dr["DatabaseID"].ToString()));
        }

        //List<CascadingDropDownNameValue> values = new List<CascadingDropDownNameValue>();

        //foreach (DataRow dr in ds)
        //{
        //    values.Add(new CascadingDropDownNameValue((string)dr["Color"], dr["ColorID"].ToString()));
        //}

        return values.ToArray();
    }

    [System.Web.Services.WebMethod]
    [System.Web.Script.Services.ScriptMethod]
    public CascadingDropDownNameValue[] GetServerValues(string knownCategoryValues, string category)
    {

        string sSQL = @"SELECT ServerId as Value, ServerName as DisplayText " +
            "FROM BabelFish.dbo.ServerList (NOLOCK) " +
            "Order By DisplayText";

        DataTable dt = DatabaseAccessing.DatabaseConnection.GetDataTable(sSQL);

        List<CascadingDropDownNameValue> values = new List<CascadingDropDownNameValue>();

        // tried manually adding if it was issue with data set but did not work eihter
        //values.Add(new CascadingDropDownNameValue("testdispally1", "1"));
        //values.Add(new CascadingDropDownNameValue("testdispally2", "2"));


        for (int i = 0; i < dt.Rows.Count; i++)
        {
            DataRow dr = dt.Rows[i];
            values.Add(new CascadingDropDownNameValue((string)dr["DisplayText"], dr["DatabaseID"].ToString()));
        }


        return values.ToArray();
    }



}// end class

Answer 1

A friend found the solution for me. The code was fine but the AjaxControlToolkit.dll was not registered correctly (or something) for this particular functionality. It worked/was registered for other functionality in the toolkit. He used NUGET to download the ajax tool kit and install it as a stand alone package and point to the package (instead of directly to the .dll's as I was doing) and it worked fine.

Just have to test/confirm this configuration works when posted to the server (I had issues with the .dll not working on the server based off the registered path for the .dll when it was posted to the server).