using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Runtime.Serialization.Formatters;

using System.IO;

using System.Data;

using System.ComponentModel.DataAnnotations;

using System.Globalization;

using System.Reflection;

using System.Collections.ObjectModel;

using System.Dynamic;

​

using System.Text.Json;

using System.Text.Json.Serialization;

​

using Newtonsoft.Json.Linq;

​

using NUnit.Framework; // Throws NUnit.Framework.AssertionException

​

//https://stackoverflow.com/questions/72640451/create-json-object-using-system-text-json#72640451

​

    class TestClass

    {

        public static void Test()

        {

            var result = new 

            {

                Status = "ok",

                TotalDuration = new 

                {

                    TotalSeconds = 101.2M,

                },

                Entries = new []

                {

                    new

                    {

                        Key = "some key",

                        Value = new

                        {

                            Status = "ok",

                            Duration = new

                            {

                                TotalSeconds = 101.2M,

                            },

                            Description = "my description",

                        },

                    },

                },

            };

            string json1, json2;

            Console.WriteLine("Result of serializing with System.Text.Json:");

            {

                var json = new Dictionary<string, object>

                {

                    ["Status"] = result.Status.ToString(),

                    ["Duration"] = result.TotalDuration.TotalSeconds.ToString(NumberFormatInfo.InvariantInfo),

                };

​

                var entries = result.Entries.ToDictionary(

                    d => d.Key,

                    d => new { Status = d.Value.Status.ToString(), Duration = d.Value.Duration.TotalSeconds.ToString(NumberFormatInfo.InvariantInfo), Description = d.Value.Description } );

                if (entries.Count > 0)

                    json.Add("result", entries);

                var newJson = JsonSerializer.Serialize(json, new JsonSerializerOptions { WriteIndented = true });

                Console.WriteLine(newJson);

                json1 = newJson;

            }

            Console.WriteLine("Result of serializing with Json.NET:");

            {

                var json = new JObject(

                    new JProperty("Status", result.Status.ToString()),

                    new JProperty("Duration", result.TotalDuration.TotalSeconds.ToString()));

                if (result.Entries.Any())

                {

                    var entries = new JObject(result.Entries

                                              .Select(d => new JProperty(d.Key, new JObject(new JProperty("Status", d.Value.Status.ToString()), new JProperty("Duration", d.Value.Duration.TotalSeconds.ToString()), new JProperty("Description", d.Value.Description)))));

​

                    json.Add(new JProperty("result", entries));

                }

                var newJson = json.ToString();

                Console.WriteLine(newJson);

                json2 = newJson;

            }

            Assert.That(JToken.DeepEquals(JToken.Parse(json1), JToken.Parse(json2)));

        }   

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: {0} ({1}), {2}", System.Runtime.InteropServices.RuntimeInformation.FrameworkDescription , Environment.Version, Environment.OSVersion);

            Console.WriteLine("System.Text.Json version: " + typeof(JsonSerializer).Assembly.FullName);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Failed with unhandled exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​