AJAX的应用程序，免不了经常需要在页面和服务之间异步传输数据。我已经多次写过这方面的东西。下面还是有一个比较经典的案例，我认为掌握到这些，那么处理异步请求的时候就相当方便了。
第一部分：客户端页面
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm3.aspx.cs" Inherits="WebApplication1.WebForm3" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> <script src="jquery-1.3.2-vsdoc.js" type="text/javascript"></script> <script src="json2.js" type="text/javascript"></script> <script type="text/javascript"> $(function() { //构造一个json对象，很类似于C#中的匿名类型 var employee = { Name: "chenxizhang", Country: "China", Orders: [ { OrderID: 10248 }, { OrderID: 10249 } ] }; //发送POST请求，数据也是json格式。但数值部分需要转换为字符串 $.post("EmployeeHandler.ashx", { data: JSON.stringify(employee) }, function(result) { var r = JSON.parse(result); alert(r.Message); }); }); </script> </head> <body> <form id="form1" runat="server"> <div> </div> </form> </body> </html>
第二部分：ashx部分
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Services; using System.Runtime.Serialization.Json; using System.Runtime.Serialization; using System.IO; using System.Text; //必须添加System.ServiceModel.Web和System.Runtime.Serialization的引用 namespace WebApplication1 { /// <summary> /// $codebehindclassname$ 的摘要说明 /// </summary> [WebService(Namespace = "http://tempuri.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] public class EmployeeHandler : IHttpHandler { public void ProcessRequest(HttpContext context) { var ser = new DataContractJsonSerializer(typeof(Employee)); var data = context.Request["data"]; var ms = new MemoryStream(Encoding.UTF8.GetBytes(data)); var emp = (Employee)ser.ReadObject(ms); ms.Close(); //此时已经得到了相应的Employee实例，可以进行服务器端的处理 var ser2 = new DataContractJsonSerializer(typeof(ActionResult)); var ms2 = new MemoryStream(); var result = new ActionResult() { Code = 200, Message = "成功" }; ser2.WriteObject(ms2, result); ms2.Position = 0; var buffer = new byte[ms2.Length]; ms2.Read(buffer, 0, buffer.Length); ms2.Close(); context.Response.Write(Encoding.UTF8.GetString(buffer)); //返回结果 } public bool IsReusable { get { return false; } } } [DataContract] public class Employee { [DataMember] public string Name { get; set; } [DataMember] public string Country { get; set; } [DataMember] public OrderItem[] Orders { get; set; } } [DataContract] public class OrderItem { [DataMember] public int OrderID { get; set; } } [DataContract] public class ActionResult { [DataMember] public int Code { get; set; } [DataMember] public string Message { get; set; } } } 第三部分：进一步的优化，编写两个扩展方法（这是C# 3.0的新特性）
/// <summary> /// 这个类型实现了对JSON数据处理的一些扩展方法 /// </summary> public static class JsonExtensions { /// <summary> /// 根据一个字符串，进行JSON的反序列化，转换为一个特定类型 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="data"></param> /// <returns></returns> public static T ToJsonObject<T>(this string data) { var serializer = new DataContractJsonSerializer(typeof(T)); var ms = new MemoryStream( Encoding.UTF8.GetBytes(data)); var result = (T)serializer.ReadObject(ms); ms.Close(); return result; } /// <summary> /// 将任何一个对象转换为JSON字符串 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="obj"></param> /// <returns></returns> public static string ToJsonString<T>(this T obj) { var serializer = new DataContractJsonSerializer(typeof(T)); var ms = new MemoryStream(); serializer.WriteObject(ms, obj); ms.Position = 0; var result = Encoding.UTF8.GetString(ms.GetBuffer()); ms.Close(); return result; } }
这样，在ashx里面的代码就很简单了
var emp = context.Request["data"].ToJsonObject<Employee>(); var result = new ActionResult() { Code = 200, Message = "成功" }; context.Response.Write(result.ToJsonString());
不错吧，这样以后处理Json就是如此容易
通过Json来传递数据，可以避免以前用传统的post或者get方面拼接字符串中的麻烦