Newtonsoft.Json code

序列化 

Product product = new Product();
product.ExpiryDate = new DateTime(2008, 12, 28);

JsonSerializer serializer = new JsonSerializer();
serializer.Converters.Add(new JavaScriptDateTimeConverter());
serializer.NullValueHandling = NullValueHandling.Ignore;

using (StreamWriter sw = new StreamWriter(@"c:json.txt"))
using (JsonWriter writer = new JsonTextWriter(sw))
{
    serializer.Serialize(writer, product);
    // {"ExpiryDate":new Date(1230375600000),"Price":0}
}

 JsonReader读Json字符串

string jsonText = @"{""input"" : ""value"", ""output"" : ""result""}";
JsonReader reader = new JsonTextReader(new StringReader(jsonText));

while (reader.Read())
{
    Console.WriteLine(reader.TokenType + "		" + reader.ValueType + "		" + reader.Value);
}

JsonWriter写字符串

StringWriter sw = new StringWriter();
JsonWriter writer = new JsonTextWriter(sw);

writer.WriteStartObject();
writer.WritePropertyName("input");
writer.WriteValue("value");
writer.WritePropertyName("output");
writer.WriteValue("result");
writer.WriteEndObject();
writer.Flush();

string jsonText = sw.GetStringBuilder().ToString();
Console.WriteLine(jsonText);

使用JObject读写字符串

JObject jo = JObject.Parse(jsonText);
string[] values = jo.Properties().Select(item => item.Value.ToString()).ToArray();

using Newtonsoft.Json;  

using Newtonsoft.Json.Linq;  

string jsonText = "[{'a':'aaa','b':'bbb','c':'ccc'},{'a':'aaa2','b':'bbb2','c':'ccc2'}]";  

    JArray ja =(JArray) JsonConvert.DeserializeObject(jsonText);  

    JObject o = (JObject)ja[1];  

    Console.WriteLine(o["a"]);  

    Console.WriteLine(ja[1]["a"]); 

 JsonSerializer读写对象(基于JsonWriter与JsonReader)

string jsonArrayText1 = "[{'a':'a1','b':'b1'},{'a':'a2','b':'b2'}]";
JArray ja = (JArray)JsonConvert.DeserializeObject(jsonArrayText1);
string ja1a = ja[1]["a"].ToString();
//或者
JObject o = (JObject)ja[1];
string oa = o["a"].ToString();

嵌套格式

string jsonText = "{"beijing":{"zone":"海淀","zone_en":"haidian"}}";
JObject jo = (JObject)JsonConvert.DeserializeObject(jsonText);
string zone = jo["beijing"]["zone"].ToString();
string zone_en = jo["beijing"]["zone_en"].ToString();

自定义类Project

class Project
{
    public string Input { get; set; }
    public string Output { get; set; }
}

Project p = new Project() { Input = "stone", Output = "gold" };
JsonSerializer serializer = new JsonSerializer();
StringWriter sw = new StringWriter();
serializer.Serialize(new JsonTextWriter(sw), p);
Console.WriteLine(sw.GetStringBuilder().ToString());

StringReader sr = new StringReader(@"{""Input"":""stone"", ""Output"":""gold""}");
Project p1 = (Project)serializer.Deserialize(new JsonTextReader(sr), typeof(Project));
Console.WriteLine(p1.Input + "=>" + p1.Output);

 契约方式：使用System.Runtime.Serialization.dll提供的DataContractJsonSerializer或者 JsonReaderWriterFactory实现

Project p = new Project() { Input = "stone", Output = "gold" };
DataContractJsonSerializer serializer = new DataContractJsonSerializer(p.GetType());
string jsonText;

using (MemoryStream stream = new MemoryStream())
{
    serializer.WriteObject(stream, p);
    jsonText = Encoding.UTF8.GetString(stream.ToArray());
    Console.WriteLine(jsonText);
}

using (MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(jsonText)))
{
    DataContractJsonSerializer serializer1 = new DataContractJsonSerializer(typeof(Project));
    Project p1 = (Project)serializer1.ReadObject(ms);
    Console.WriteLine(p1.Input + "=>" + p1.Output);
}

 这里要注意，这里的Project类和成员要加相关的Attribute：

[DataContract]
class Project
{
    [DataMember]
    public string Input { get; set; }
    [DataMember]
    public string Output { get; set; }
}

实用参考：
JSON验证工具：http://jsonlint.com/
JSON简明教程：http://www.w3school.com.cn/json/
Newtonsoft.Json类库下载：http://json.codeplex.com/