C#将数据转换为指定格式的json字符串

    //实体类
    class ReturnJson
    {
        public class Achievement 
        {
            private int english;
            private int math;

            public int English { get => english; set => english = value; }
            public int Math { get => math; set => math = value; }

        }
        private String name;
        private int age;
        private String address;
        private List<Achievement> li=new List<Achievement>();

        public string Name { get => name; set => name = value; }
        public int Age { get => age; set => age = value; }
        public string Address { get => address; set => address = value; }
        public List<Achievement> Li { get => li; set => li = value; }
    }

　　

    //测试类
    class Program
    {
        static void Main(string[] args)
        {
            //初始数据
            ReturnJson rj = new ReturnJson
            {
                Name = "wen",
                Age = 12,
                Address = "adadd"
            };
            //给list集合添加数据
            rj.Li.Add(new ReturnJson.Achievement
            {
                Math = 23,
                English = 34
            });
            rj.Li.Add(new ReturnJson.Achievement
            {
                Math = 25,
                English = 354
            });

            //将对象序列化为字符串
            string json = JsonConvert.SerializeObject(rj);

            //测试输出数据
            //Console.Write(rj.Li[0].English);
            Console.Write(json);

            //Console.ReadKey(); //等待用户按下任意键，一次读入一个字符。
            Console.ReadLine();//等待直到用户按下回车，一次读入一行。
        }
    }

　　输出的json字符串如下:

{
  "Name": "wen",
  "Age": 12,
  "Address": "adadd",
  "Li": [
    {
      "English": 34,
      "Math": 23
    },
    {
      "English": 354,
      "Math": 25
    }
  ]
}

　　

注意:using Newtonsoft.Json;自己导入