程序代码：

using System;
using System.Collections.Generic;
using using System.Data;
using System.Drawing;
using using System.Linq;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Json;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Direct
{
    public partial class Form1 : Form
    {
        [DataContract]
        public class MyClass
        {
            [DataMember]
            public Dictionary<int, string> myDictionary = new Dictionary<int, string>();
        }
        MyClass myClass = new MyClass();

        public Form1()
        {
            InitializeComponent();

            myClass.myDictionary.Add(1, "C#");
            myClass.myDictionary.Add(2, "C++");
            myClass.myDictionary.Add(3, "");
            myClass.myDictionary.Add(4, "MVC");
        }

        private void button1_Click(object sender, EventArgs e)
        {
            ObjectToJson(myClass, "123.json");
        }

        private void button2_Click(object sender, EventArgs e)
        {
            myClass.myDictionary.Clear();
            myClass =JsonFileToObject<MyClass>("123.json");
        }

        /// 将对象序列化为json文件
        public static void ObjectToJson<T>(T t, string path) where T : class
        {
            DataContractJsonSerializer formatter = new DataContractJsonSerializer(typeof(T));
            using (FileStream stream = new FileStream(path, FileMode.Create))
            {
                formatter.WriteObject(stream, t);
            }
        }

        /// json字符串转成对象
        public static T JsonToObject<T>(string json) where T : class
        {
            DataContractJsonSerializer formatter = new DataContractJsonSerializer(typeof(T));
            using (MemoryStream stream = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(json)))
            {
                T result = formatter.ReadObject(stream) as T;
                return result;
            }
        }

        /// json文件转成对象
        public static T JsonFileToObject<T>(string path) where T : class
        {
            string str = File.ReadAllText(path, Encoding.UTF8);
            return JsonToObject<T>(str);
        }
    }
}

[此贴子已经被作者于2022-8-15 20:13编辑过]