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()));
});