Create JSON for jquery datatables

Question

I'm really stuck with this..I have never used web services but needed a web service to supply json data for a jquery datatable.

The following webservice ( i thought ) should create a json file but its actually creating an xml file

Here is the routine 

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Services;

using System.Text;

using System.Web.Script.Services;

using System.Data;

using System.Data.SqlClient;

using System.Configuration;

using System.ServiceModel.Web;

namespace NewWebsite

{

    /// <summary>

    /// Summary description for WebService1

    /// </summary>

    [WebService(Namespace = "NewWebsite")]

    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]

    [System.ComponentModel.ToolboxItem(false)]

    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.

    [System.Web.Script.Services.ScriptService]

    public class WebService1 : System.Web.Services.WebService

    {

        [WebMethod]

        [ScriptMethod(UseHttpGet = true)]

        [WebInvoke(ResponseFormat = WebMessageFormat.Json,

         BodyStyle = WebMessageBodyStyle.Bare, Method = "GET")]

        public string GetItems()

        {

            var sb = new StringBuilder();

            var connectionString = ConfigurationManager.ConnectionStrings["kudos"].ConnectionString;

            SqlConnection conn = new SqlConnection(connectionString);

            try

            { conn.Open(); }

            catch (Exception e)

            { Console.WriteLine(e.ToString()); }

            var DB = new SqlCommand();

            DB.Connection = conn;

            DB.CommandText = "select customer_name,town from customers";

            var data = DB.ExecuteReader();

            string outputJson = string.Empty;

            while (data.Read())

            {

                sb.Append("{");

                sb.AppendFormat(@"""Name"": ""{0}""", data["Customer_Name"]);

                sb.Append(",");

                sb.AppendFormat(@"""Town"": ""{0}""", data["Town"]);

                sb.Append("},");

            }

            outputJson = sb.ToString();

            return outputJson;

        }

    }

}

The output looks like this :-

<string xmlns="NewWebsite">
{"Name": "A Q S Bathrooms Lyons Electrical","Town": "SPENNYMOOR"},{"Name": "H & S Bathrooms","Town": "BLACKBURN"},{"Name": "Homecare Heating","Town": "DARLINGTON"},{"Name": "Midland Showers & Bathrooms Ltd","Town": "NOTTINGHAM"},{"Name": "City Plumbing Supplies","Town": "CARDIFF"},{"Name": "Home & Trade Ltd","Town": "BURTON-ON-TRENT"},{"Name": "City Plumbing Supplies DUPP AT 4838","Town": "PLYMOUTH"},{"Name": "City Plumbing Supplies","Town": "HALIFAX"},{"Name": "Harmony Interiors","Town": "LUTON"},{"Name": "Pure Bathrooms","Town": "CAMBRIDGE"},{"Name": "Bathrooms Kitchens By Design","Town": "NUNEATON"},{"Name": "Fire & Water","Town": "WHITEHAVEN"},{"Name": "City Plumbing Supplies","Town": "EXETER"},{"Name": "City Plumbing Supplies","Town": "GOSPORT"},{"Name": "City Plumbing Supplies","Town": "GLASGOW"},................................................

Any idea why ?

If anyone has a good example of how to link jquery datatables with sql via json I;d be REALLY happy !