1.使用微软自带的System.Web.Extensions.dll转换，该DLL文件一般存在于如下路径：c:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Web.Extensions.dll

    具体操作如下：

    //将List集合转换为Json字符串，必须应用上面的DLL文件，同时引用using System.Web.Script.Serialization;命名空间

    JavaScriptSerializer serializer = new JavaScriptSerializer();

    List<Person> list = new List<Person>();

    for (int i = 0; i < 10; i++)

    {

       Person p = new Person("张三" + i, "重庆" + i, "10" + i);

       list.Add(p);

    }

    MessageBox.Show(serializer.Serialize(list));

    //将Json字符串转换为集合，Person为自己定义的实体类

    string json = "[{'Address':'重庆0','Age':'100','Name':'张三0'},{'Address':'重庆1','Age':'101','Name':'张三1'}]";

    JavaScriptSerializer serializer = new JavaScriptSerializer();

    List<Person> list = serializer.Deserialize<List<Person>>(json);

2.可以借助开源的Newtonsoft.Json.dll进行转换

3.引用微软如下两个DLL

    //注意引用：System.Runtime.Serialization，System.ServiceModel.Web

    // 从一个对象信息生成Json串

    public static string ObjectToJson(object obj)

    {

       DataContractJsonSerializer serializer = new DataContractJsonSerializer(obj.GetType());

       MemoryStream stream = new MemoryStream();

       serializer.WriteObject(stream, obj);

       byte[] dataBytes = new byte[stream.Length];

       stream.Position = 0;

       stream.Read(dataBytes, 0, (int)stream.Length);

       return Encoding.UTF8.GetString(dataBytes);

    }

    // 从一个Json串生成对象信息

    public static object JsonToObject(string jsonString, object obj)

    {

       DataContractJsonSerializer serializer = new DataContractJsonSerializer(obj.GetType());

       MemoryStream mStream = new MemoryStream(Encoding.UTF8.GetBytes(jsonString));

       return serializer.ReadObject(mStream);

    }