项目下载:JavaScriptSerializer_对JSON对象序列化与反序列化及过滤器
利用<JavascriptSerializer类> 进行Json对象的序列化和反序列化
1. 首先, JavascriptSerializer类所在名空间: using System.Web.Script.Serialization;
2. 相关的3篇文章, 标记下:
使用JavaScriptSerializer进行JSON序列化
注意: 是复杂对象.
JSON是Javascript中常用的数据格式,然而,在.NET 2.0中没有内置序列化JSON的类,原因估计是当时Ajax尚未兴起。后来就有人写了一个Json.NET类库。.NET 3.5新增了一个把对象序列化为JSON字符串的类JavaScriptSerializer。这个类位于System.Web.Script.Serialization名字空间中(非Web项目需要添加System.Web.Extensions.dll引用),其使用方法也是非常简单的:
// 分类
public class Category
{
public int CategoryId { get; set; } // 分类编号
public string CategoryName { get; set; } // 分类名
}
Category testCategory = new Category()
{
CategoryId = 1,
CategoryName = "Test"
};
JavaScriptSerializer serializer = new JavaScriptSerializer();
Console.Write(serializer.Serialize(testCategory)); // 调用Serialize方法进行序列化
如果不希望序列化某个属性,可以给该属性标记为ScriptIgnore:
public class Category
{
[ScriptIgnore]
public int CategoryId { get; set; }
public string CategoryName { get; set; }
}
事实上,Serialize方法是个递归方法,会递归地序列化对象的属性,因此在序列化一个复杂对象(比如DataTable)时往往会出现“循环引用”的异常,这时候就需要针对复杂类型自定义一个转换器。下面是DataTable的转换器,原理是把DataTable转换成一个字典列表后再序列化:
/// <summary>
/// DataTable JSON转换类
/// </summary>
public class DataTableConverter : JavaScriptConverter
{
public override IDictionary<string, object> Serialize(object obj, JavaScriptSerializer serializer)
{
DataTable dt = obj as DataTable;
Dictionary<string, object> result = new Dictionary<string, object>();
List<Dictionary<string, object>> rows = new List<Dictionary<string, object>>();
foreach (DataRow dr in dt.Rows)
{
Dictionary<string, object> row = new Dictionary<string, object>();
foreach (DataColumn dc in dt.Columns)
{
row.Add(dc.ColumnName, dr[dc.ColumnName]);
}
rows.Add(row);
}
result["Rows"] = rows;
return result;
}
public override object Deserialize(IDictionary<string, object> dictionary, Type type, JavaScriptSerializer serializer)
{
throw new NotImplementedException();
}
/// <summary>
/// 获取本转换器支持的类型
/// </summary>
public override IEnumerable<Type> SupportedTypes
{
get { return new Type[] { typeof(DataTable) }; }
}
}
所有自定义的转换器都要继承于JavaScriptConverter,并实现Serialize、Deserialize方法和SupportedTypes属性,其中SupportedTypes属性用于枚举此转换器支持的类型。定义了一个新的转换器后需要将其实例化并注册到JavaScriptSerializer对象:
JavaScriptSerializer JsonSerializer = new JavaScriptSerializer();
JsonSerializer.RegisterConverters(
new JavaScriptConverter[]
{
new DataTableConverter()
}
);
对于DateTime类型,JavaScriptSerializer默认将其序列化为 "\/Date(ticks)\/" 格式的字符串,这明显需要Javascript作进一步的解释,非常多余。笔者建议各位根据需要添加一个DateTime类型的转换器。
====================================
第二篇:
Asp.net Ajax WebService 实现循环引用(自定义JavascriptConverter)
准备技术:
1.简单的WebService编写;
2.了解Asp.net Ajax 客户端访问WebService
内容:
asp.net ajax框架在去年看过,只是些基本的使用,并没有过多的去研究它的原理。最近在一个项目中要实现客户端访问WebService并返回DataTable类型的数据,当我调用一个返回DataTable的方法时,不能返回成功,在错误的回调函数中告诉我DataTable是一个循环应用类型,不能序列化。当是想过把DataTable替换成其他类型的数据如ArrayList或则Array等,可是有点心不甘,所以查过各个方面的资料,告诉我微软已经提供了一个解决DataTable的JavaScriptConverter的dll文件,当我在web.config中添加了对这个JavascriptConverter引用即可以将DataTable序列化成Json字符串了。
好了,废话不多说了。下面就自己来做个循环应用的实例,并通过自定义JavascriptConverter来解决循环引用的问题。本文只会简单的介绍下服务器端序列化数据类型到Json的过程,不会太深入。
首先先来定义两个类,想了半天最好的实例就是一对夫妻,一个老公只有一个老婆,这是婚姻法规定的,所以老公类型跟老婆类型就可以达到实例中的循环引用。看下两个类型的类试图:
其实两个类里面的内容都很简单,Husband.cs:
using System;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.ComponentModel;
public class Husband
{
private string _firstName;
public string FirstName
{
get { return _firstName; }
set { _firstName = value; }
}
private string _lastName;
public string LastName
{
get { return _lastName; }
set { _lastName = value; }
}
private Wife _wife;
public Wife Wife
{
get { return _wife; }
set { _wife = value; }
}
}
Wife.cs:
using System;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.ComponentModel;
public class Wife
{
private string _firstName;
public string FirstName
{
get { return _firstName; }
set { _firstName = value; }
}
private string _lastName;
public string LastName
{
get { return _lastName; }
set { _lastName = value; }
}
private Husband _husband;
public Husband Husband
{
get { return _husband; }
set { _husband = value; }
}
}
然后我定义了个Webservice类用来提供Client的访问,HusbandService.cs:
using System;
using System.Collections;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Xml.Linq;
using System.Web.Script.Services;
/// <summary>
/// Husband's Method
/// </summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[ScriptService]
public class HusbandService : System.Web.Services.WebService {
public HusbandService () {
//Uncomment the following line if using designed components
//InitializeComponent();
}
[WebMethod]
public Husband GetHusband()
{
Husband hansband = new Husband();
hansband.FirstName = "Henllyee";
hansband.LastName = "Cui";
Wife wife = new Wife();
wife.FirstName = "Throwen";
wife.LastName = "Yang";
hansband.Wife = wife;
wife.Husband = hansband;
return hansband;
}
}
我在一个asp.net 页面中通过asp.net ajax对GetHusband()的应用的,JavascriptConverter.aspx:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="JavascriptConverter.aspx.cs" Inherits="_Default" %>
<!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>JavaScriptConverter Demo</title>
</head>
<body>
<form >