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 Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Serialization;    

​

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

​

//https://stackoverflow.com/questions/59935580/why-does-newtonsoft-json-jsonconvert-serializeobject-surround-result-with-quotes

​

    class TestClass

    {

        public static void Test()

        {

            DateTime date = new DateTime(2020, 01, 27);

            var s = date.ToString("s", CultureInfo.InvariantCulture);

​

            Console.WriteLine("Result of 'date.ToString(\"s\", CultureInfo.InvariantCulture)':");

            Console.WriteLine(s);

            string str = Newtonsoft.Json.JsonConvert.SerializeObject(date, Newtonsoft.Json.Formatting.None,

                new Newtonsoft.Json.JsonSerializerSettings() {

                     DateFormatHandling = Newtonsoft.Json.DateFormatHandling.IsoDateFormat });      

​

            Console.WriteLine("\nResult of JSON serialization:");

            Console.WriteLine(str);

        }   

    }

​

    public class Program

    {

        public static void Main()

        {

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

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

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

                Console.WriteLine(ex);

                throw;

            }

        }

        public static string GetNetCoreVersion()

        {

            //https://techblog.dorogin.com/how-to-detect-net-core-version-in-runtime-ecd65ad695be

            //

            var assembly = typeof(System.Runtime.GCSettings).GetTypeInfo().Assembly;

            var assemblyPath = assembly.CodeBase.Split(new[] { '/', '\\' }, StringSplitOptions.RemoveEmptyEntries);

            int netCoreAppIndex = Array.IndexOf(assemblyPath, "Microsoft.NETCore.App");

            if (netCoreAppIndex > 0 && netCoreAppIndex < assemblyPath.Length - 2)

                return assemblyPath[netCoreAppIndex + 1];

            return null;

        }

    }

​