Asp.net无刷新调用后台实体类数据并以Json格式返回

public class Temp
{
    public int Index { get; set; }
    public string Description { get; set; }
    public string ImagePath { get; set; }
    public DateTime MyDate { get; set; }
}

   //数据源 
    List<Temp> listTemp = new List<Temp>()
    {
        new Temp(){ Index=1,ImagePath="Desert.jpg", Description="图片1",MyDate=DateTime.Now},
        new Temp(){Index=2,ImagePath="Chrysanthemum.jpg", Description="图片2",MyDate=DateTime.Now},
        new Temp(){Index=3,ImagePath="Penguins.jpg", Description="图片3",MyDate=DateTime.Now},
        new Temp(){Index=4,ImagePath="Jellyfish.jpg", Description="图片4",MyDate=DateTime.Now},
        new Temp(){Index=5,ImagePath="Tulips.jpg", Description="图片5",MyDate=DateTime.Now}
    };

    public void ProcessRequest(HttpContext context)
    {
        string index = context.Request["Index"];
        string jsonStr = string.Empty;
        foreach (var item in listTemp)
        {
            if (item.Index.ToString() == index)
            {
                JavaScriptSerializer serializer = new JavaScriptSerializer();
                jsonStr = serializer.Serialize(item); //序列化为json格式
                break;
            }
        }

        context.Response.Write(jsonStr);
    }

  $.getJSON("imageChange.ashx", { Index: i - 1 }, function (result) {
     $("#<%=lblDescription.ClientID %>").text(result.Description);
 $("#<%=Image1.ClientID %>").attr("src", path + result.ImagePath.substr(result.ImagePath.lastIndexOf('/') + 1));

    var d = eval("new " + result.MyDate.replace(/\//g, ""));
                    $("#<%=lblDate.ClientID %>").text(Todate(d.ToLocalTime().toString()));
 });

//ToLocalTime()将UTC格式数据转换成标准日期格式
//注意JavaScriptSerializer会将日期序列号为自1970年1月1号的刻度值，所以js获取的时间值需做一些处理转换成标准日期格式
//详见http://msdn.microsoft.com/zh-cn/library/system.web.script.serialization.javascriptserializer.aspx