Newtonsoft.Json使用，C# Json文件读取，写入

 用学校作为例子，有学校名称，学校下面有班级，班级有名字，班级下面有学生，这里面有数组，有字段

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace JsonDemo
{
    public class School
    {
        public string SchoolName { get; set; }
        public List<Grade> Grades { get; set; } =  new List<Grade>();

    }

    public class Grade
    {
        public string GradeName { get; set; }
        public List<Student> Students { get; set; } = new List<Student>();
    }

    public class Student
    {
        public string StudentName { get; set; }
    }
}

主程序 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace JsonDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            School school = new School();
            school.SchoolName = "某某某小学";

            Grade grade1 = new Grade();
            grade1.GradeName = "1班";

            Student student = new Student();
            student.StudentName = "小张";
            grade1.Students.Add(student);

            Grade grade2 = new Grade();
            grade2.GradeName = "2班";
            Grade grade3 = new Grade();
            grade3.GradeName = "3班";

            school.Grades.Add(grade1);
            school.Grades.Add(grade2);
            school.Grades.Add(grade3);

            ParameterByJson parameterByJson = new ParameterByJson();

            string jsonText1 = parameterByJson.SchoolToText(school);

            School school1 = parameterByJson.TextToSchool(jsonText1);

            parameterByJson.WriteText("test.json", jsonText1);

            string jsonText2 = parameterByJson.ReadFileText("test.json");

            School school2 = parameterByJson.TextToSchool(jsonText2);
        }
    }
}

Json类，包含了json数组的生成和转换

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace JsonDemo
{
    public class ParameterByJson
    {
        /// <summary>
        /// 读取JSON
        /// </summary>
        private JObject ReadStringJson(string json)
        {
            JObject jObject = (JObject)JsonConvert.DeserializeObject(json);
            return jObject;
        }

        /// <summary>
        /// 读取JSON文件
        /// </summary>
        private JObject ReadFileJson(string jsonFile)
        {
            try
            {
                using (System.IO.StreamReader file = System.IO.File.OpenText(jsonFile))
                {
                    using (JsonTextReader reader = new JsonTextReader(file))
                    {
                        JObject jObject = (JObject)JToken.ReadFrom(reader);
                        return jObject;
                    }
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
                return null;
            }
        }

        public string ReadFileText(string jsonFile)
        {
            try
            {
                string text = "";
                using (System.IO.StreamReader file = System.IO.File.OpenText(jsonFile))
                {
                    text = file.ReadToEnd();
                }
                return text;
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
                return null;
            }
        }

        /// <summary>
        /// 写入JSON文件
        /// </summary>
        /// <param name="jsonFile"></param>
        /// <param name="jObject"></param>
        private void WriteJson(string jsonFile, JObject jObject)
        {
            using (System.IO.StreamWriter file = new System.IO.StreamWriter(jsonFile))
            {
                file.Write(jObject.ToString());
            }
        }

        /// <summary>
        /// 写入JSON文件
        /// </summary>
        /// <param name="jsonFile"></param>
        /// <param name="jObject"></param>
        public void WriteText(string jsonFile, string jsonStr)
        {
            using (System.IO.StreamWriter file = new System.IO.StreamWriter(jsonFile))
            {
                file.Write(jsonStr);
            }
        }

        /// <summary>
        /// 效验文件夹，没有就创建
        /// </summary>
        private void DirectoryCheak(string path)
        {
            if (false == System.IO.Directory.Exists(path))
            {
                System.IO.Directory.CreateDirectory(path);
            }
        }

        public string SchoolToText(School school)
        {
            try
            {
                //设定小驼峰模式，属性名首字母小写
                var setting = new JsonSerializerSettings
                {
                    ContractResolver = new Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver()
                };

                return JsonConvert.SerializeObject(school, setting);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
                return null;
            }
        }

        public string SchoolToTextComplex(School school)
        {
            try
            {
                JObject jObject = new JObject();
                jObject.Add("school", new JObject());
                JObject jObjectSchool = (JObject)jObject["school"];
                jObjectSchool.Add("schoolName", new JObject());
                jObjectSchool["schoolName"] = school.SchoolName;
                jObjectSchool.Add("grades", new JArray());
                JArray JArrayGrades = (JArray)jObjectSchool["grades"];

                for (int i = 0; i < school.Grades.Count; i++)
                {
                    JObject jObjectGrade = new JObject();
                    jObjectGrade.Add("gradeName", new JObject());
                    JObject jObjectGradeName = (JObject)jObjectGrade["gradeName"];
                    JArrayGrades.Add(jObjectGrade);
                }
                //太复杂了，省略了

                return JsonConvert.SerializeObject(jObject);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
                return null;
            }
        }

        public School TextToSchool(string jsonText)
        {
            try
            {
                if (!String.IsNullOrEmpty(jsonText))
                {
                    //设定小驼峰模式，属性名首字母小写
                    var setting = new JsonSerializerSettings
                    {
                        ContractResolver = new Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver()
                    };
                    return JsonConvert.DeserializeObject<School>(jsonText, setting);
                }
                else
                {
                    return null;
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
                return null;
            }
        }

        public School TextToSchoolComplex(string jsonText)
        {
            try
            {
                if (!String.IsNullOrEmpty(jsonText))
                {
                    JObject jObject = (JObject)JsonConvert.DeserializeObject(jsonText);
                    School school = new School();
                    school.SchoolName = jObject["school"].ToString();

                    JArray items = JArray.Parse(jObject["grades"].ToString());
                    List<Grade> grades = new List<Grade>();
                    foreach (var item in items)
                    {
                        JObject itmeTemp = JObject.Parse(item.ToString());
                        Grade grade = new Grade();
                        grade.GradeName = itmeTemp["gradeName"].ToString();
                        grades.Add(grade);
                    }

                    school.Grades = grades;
                    //省略一部分，太麻烦了
                    return school;
                }
                else
                {
                    return null;
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
                return null;
            }
        }
    }
}

Demo地址

https://download.csdn.net/download/g313105910/16346139