AutoComplete Textbox

Hi guys, i am trying to do the auto complete textbox using entity data model but i am getting this error "parsererror"  please help, bellow is my code:

 

 

 

<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="AutoComplete._Default" %>

Auto Complete

Type Company Name:

 

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Script.Services;
using System.Web.Services;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace AutoComplete
{
public partial class _Default : Page
{
protected void Page_Load(object sender, EventArgs e)
{

}
[WebMethod]
[ScriptMethod(ResponseFormat= ResponseFormat.Json)]
public static List GetCompanyName(string pre)
{
List allCompanyName = new List();
using (MyDatabaseEntities dc = new MyDatabaseEntities ())
{
allCompanyName = (from a in dc.TopCompanies
where a.CompanyName.StartsWith(pre)
select a.CompanyName).ToList();
}
return allCompanyName;
}
}
}