Ext在模型中通过代理加载数据

Ext4中使用模型代理加载数据，利用NorthWind数据库中的Customers表

Ext.onReady(function ()
{
    Ext.regModel("Customers", {
        fields: [
            //定义模型字段
            { name: "CustomerID", type: "int" },
            { name: "CompanyName", type: "string" },
            { name: "ContactName", type: "string" },
            { name: "ContactTitle", type: "string" },
            { name: "Address", type: "string" },
            { name: "City", type: "string" },
            { name: "Region", type: "string" },
            { name: "PostalCode", type: "string" },
            { name: "Country", type: "string" },
            { name: "Phone", type: "string" },
            { name:"Fax", type:"string"}
        ],
        //配置数据代理
        proxy: {
            type: "ajax",
            url:"/AjaxHandler/getCustomer.ashx"
        }
    });

    var customer = Ext.ModelManager.getModel("Customers");
    //通过代理读取数据（其中"AROUT"对应的是表Customers中的CustomerID字段）
    customer.load("AROUT", {
        success:function(rec)
        {
            Ext.Msg.alert("提示", rec.get("CompanyName"));
        }
    });
});

getCustomer.ashx代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using Ext;

namespace Ext.AjaxHandler
{
    /// <summary>
    /// getCustomer 的摘要说明
    /// </summary>
    public class getCustomer : IHttpHandler
    {

        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";
            //context.Response.Write("Hello World");

            string customerID=context.Request["id"];
            string result = "{";

            NorthwindEntities db = new NorthwindEntities();
            var query = from c in db.Customers
                        where c.CustomerID == customerID
                        select c;
            foreach (var c in query)
            {
                result += "CustomerID:\"" + c.CustomerID + "\",CompanyName:\"" + c.CompanyName + "\"";
            }
            result += "}";
            context.Response.Write(result);
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

效果如下：