C#实现Json文件读写的方法代码

//模型类，定义Json结构
    public class BaseModel
    {
        public List<ModelData> list_groupA { get; set; } = new List<ModelData>();
        public List<ModelData> list_groupB { get; set; } = new List<ModelData>();
        public List<ModelData> list_groupC { get; set; } = new List<ModelData>();
    }

    public class ModelData
    {
        public ModelData(int iD, int pointX, int pointY, string groupName)
        {
            ID = iD;
            PointX = pointX;
            PointY = pointY;
            GroupName = groupName;
        }

        public int ID { get; set; }
        public int PointX { get; set; }
        public int PointY { get; set; }
        public string GroupName { get; set; }
    }

public void SaveToFile(string filePath)
        {
            if (filePath != "")
            {
                List<ModelData> list = new List<ModelData>(100);

                for (int i = 1; i <= 100; i++)
                {
                    if (i < 50)
                    {
                        list.Add(new ModelData(i, 10, 10, "集合A"));
                    }
                    else if (i >= 50 && i < 75)
                    {
                        list.Add(new ModelData(i, 20, 20, "集合B"));
                    }
                    else
                    {
                        list.Add(new ModelData(i, 30, 30, "集合C"));
                    }
                }
                BaseModel model = new BaseModel();
                model.list_groupA = list.Where(x => x.GroupName == "集合A").ToList();
                model.list_groupB = list.Where(x => x.GroupName == "集合B").ToList();
                model.list_groupC = list.Where(x => x.GroupName == "集合C").ToList();
                string json2 = JsonConvert.SerializeObject(model);
                WriteJsonFile(filePath, json2);
            }
        }

        /// <summary>
        /// 将序列化的json字符串内容写入Json文件，并且保存
        /// </summary>
        /// <param name="path">路径</param>
        /// <param name="jsonConents">Json内容</param>
        public void WriteJsonFile(string path, string jsonConents)
        {
            try
            {
                File.WriteAllText(path, jsonConents, System.Text.Encoding.UTF8);
                MessageBox.Show("保存成功！");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

string json2 = JsonConvert.SerializeObject(list);

public void ReadJsonFile(string readFilePath)
        {
            if (File.Exists(readFilePath))
            {
                //获取文件内容
                string readString = File.ReadAllText(readFilePath);
                //反序列化：单组
                /*JArray ja = (JArray)JsonConvert.DeserializeObject(readString);
                int jaCount = ja.Count;
                ja[0]["PinHight"].ToString();*/
                //反序列化
                JObject jo = JsonConvert.DeserializeObject<JObject>(readString);
                int joCount = jo.Count;
                //获取指定位置值
                int str = jo["list_groupA"][0].Value<int>("ID");
            }
        }

/// <summary>
        /// 更新字段
        /// </summary>
        /// <param name="fileName"></param>
        public void UpdateJsonFile(string fileName)
        {
            string jsonString = File.ReadAllText(fileName, System.Text.Encoding.UTF8);//读取文件
            JObject jobject = JObject.Parse(jsonString);//解析成json
            jobject["list_student"][0]["ID"] = 111;//替换需要的文件
            string convertString = Convert.ToString(jobject);//将json装换为string
            File.WriteAllText(fileName, convertString, System.Text.Encoding.UTF8);//将内容写进jon文件中
        }