欲成为海洋大师，必知晓海中每一滴水的真名。

刚开始只是想找一个转换JSON数组的方法，结果在MSDN翻到一大把。

搜索过程中免不了碰到一大堆名词：WCF => DataContract => DataMember => DataContractJsonSerializer，然后就是不停的引入命名空间。

这一段经历，立即让我就联想到了上面引用的这句存在于某小说里面巫师的话语。静态语言真有点令人抓狂，不停的做准备，然后才可能开始工作。

对比

.NET下几种常见的解析JSON方法

主要类	命名空间	限制	内建LINQ支持
DataContractJsonSerializer	System.Runtime.Serialization.Json	通用	否
JavaScriptSerializer	System.Web.Script.Serialization	只能在Web环境使用	否
JsonArray、JsonObject、JsonValue	System.Json	只能在Silverlight中使用	是
JsonConvert、JArray、JObject、JValue、JProperty	Newtonsoft.Json	通用	是

准备数据

实体类：

    [DataContract]

    public class Person

    {

        [DataMember(Order = 0, IsRequired = true)]

        public string Name { get; set; }

        [DataMember(Order = 1)]

        public int Age { get; set; }

        [DataMember(Order = 2)]

        public bool Alive { get; set; }

        [DataMember(Order = 3)]

        public string[] FavoriteFilms { get; set; }

        [DataMember(Order = 4)]

        public Person Child { get; set; }

    }

定义：

Action<object> log = o => Console.WriteLine(o);

Func<int, int, int> add = (x, y) => x + y;

var p1 = new Person {

    Age = 12,

    Alive = true,

    Name = "lj",

    FavoriteFilms = new[] { "Up", "Avatar" }

};

var p2 = new Person() { Age = 28, Name = "cy", Child = p1 };

使用DataContractJsonSerializer

帮助类：

  // using System.Runtime.Serialization.Json;

    /// <summary>

    /// 解析JSON，仿Javascript风格

    /// </summary>

    public static class JSON

    {

        public static T parse<T>(string jsonString)

        {

            using (var ms = new MemoryStream(Encoding.UTF8.GetBytes(jsonString)))

            {

                return (T)new DataContractJsonSerializer(typeof(T)).ReadObject(ms);

            }

        }

        public static string stringify(object jsonObject)

        {

            using (var ms = new MemoryStream())

            {

                new DataContractJsonSerializer(jsonObject.GetType()).WriteObject(ms, jsonObject);

                return Encoding.UTF8.GetString(ms.ToArray());

            }

        }

    }

用法：

    // 序列化

    var jsonString = JSON.stringify(new[] { p1, p2 });

    log(jsonString == JSON.stringify(new List<Person>() { p1, p2 }));   //true

    log(jsonString);

    // 反序列化，泛型集合

    JSON.parse<List<Person>>(jsonString);

    // 数组转换

    JSON.parse<Person[]>(jsonString);

输出：

[{"Name":"lj","Age":12,"Alive":true,"FavoriteFilms":["Up","Avatar"],"Child":null

},{"Name":"cy","Age":28,"Alive":false,"FavoriteFilms":null,"Child":{"Name":"lj",

"Age":12,"Alive":true,"FavoriteFilms":["Up","Avatar"],"Child":null}}]

使用JavaScriptSerializer

  // using System.Web.Script.Serialization;

    var jser    = new JavaScriptSerializer();

    var json    = jser.Serialize(new List<Person>() { p1, p2 });

    var persons = jser.Deserialize<List<Person>>(json);

使用Silverlight

  // using System.Json

    var css = "{ \"#header\" : {background:\"red\"}, layout : [5,4,1],color:\"cyan\" }";

    var style = JsonObject.Parse(css) as JsonObject;    

    (

    from s in style

    where s.Key == "color"

    select (string)s.Value

    ).First().ToString();

    // "cyan"

    // 更多操作

    style["layout"][0] = 22;

    var hd = style["#header"];

    style["body>div+p"] = hd;

    style.Remove("#header");

    var bd = new JsonObject();

    bd["border"] = "1px solid cyan";

    style["body>div+p"]["#meta"] = bd;

    style.ToString();

    // {"layout":[22,4,1],"color":"cyan","body>div+p":{"background":"red","#meta":{"border":"1px solid cyan"}}}

使用JSON.NET

  // using Newtonsoft.Json;

    var json = JsonConvert.SerializeObject(new[] { p1, p2 });

    var persons = JsonConvert.DeserializeObject<List<Person>>(json);

    var ja = JArray.Parse(jsonString);

    log(ja);	//注意，格式化过的输出

输出：

[

  {

    "Name": "lj",

    "Age": 12,

    "Alive": true,

    "FavoriteFilms": [

      "Up",

      "Avatar"

    ],

    "Child": null

  },

  {

    "Name": "cy",

    "Age": 28,

    "Alive": false,

    "FavoriteFilms": null,

    "Child": {

      "Name": "lj",

      "Age": 12,

      "Alive": true,

      "FavoriteFilms": [

        "Up",

        "Avatar"

      ],

      "Child": null

    }

  }

]

LINQ：

    var ageCount = ja.Select(j => (int)j["Age"]).Aggregate(add);

    var q = from j in ja

            where !j["Name"].Value<string>().Equals("lj")

            select (int)j["Age"];

    log(q.Aggregate(add) == ageCount);  //false

其他：

  // 与Linq to XML 相似的嵌套构造函数：

    var jo = new JObject(

                    new JProperty("age", persons.Select( p => p.Age)),

                    new JProperty("funny", true),

                    new JProperty("array", new JArray(new[] { 2, 4, 1 }))

                    );

    log(jo);

    // JObject 操作

    var css = "{ \"#header\" : {background:\"red\"}, layout : [5,4,1] }";

    var style = JObject.Parse(css);

    var bd = new JObject();

    bd["color"] = "1px solid cyan";

    style["border"] = bd;

    var hd = style["#header"];

    style["body>div+p"] = hd;

    hd.Parent.Remove();

    style["layout"][0] = 22;

    log(style);

输出：

    {

      "age": [

        12,

        28

      ],

      "funny": true,

      "array": [

        2,

        4,

        1

      ]

    }

    {

      "layout": [

        22,

        4,

        1

      ],

      "border": {

        "color": "1px solid cyan"

      },

      "body>div+p": {

        "background": "red"

      }

    }