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 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/57828460/newtonsoft-json-linq-jarray-parsestring-has-some-invalid-arguments

​

    public class ObjectId

    {

        public long Id { get; set; }

    }

​

    class TestClass

    {

        public static void Test()

        {

            TestMultiple();

            TestSingle();

            TestObjectId();

        }

        public static void TestObjectId()

        {

            var response = new 

            {

                Content = GetJson(),

            };

            var ids =  JsonConvert.DeserializeObject<List<ObjectId>>(response.Content)

                .Select(o => o.Id)

                .ToList();

            ids.Dump();

        }

        public static void TestMultiple()

        {

            var response = new 

            {

                Content = GetJson(),

            };

            var ids =  JsonConvert.DeserializeAnonymousType(response.Content, new [] { new { Id = default(long) } })

                .Select(o => o.Id)

                .ToList();

            ids.Dump();

        }   

        public static void TestSingle()

        {

            var response = new 

            {

                Content = GetJson(),

            };

            var id =  JsonConvert.DeserializeAnonymousType(response.Content, new [] { new { Id = default(long) } })

                .Select(o => o.Id)

                .Single();

            id.Dump();

        }   

        static string GetJson()

        {

            var json = @"[{

    ""Id"": 2021,

    ""CategoryId"": null,

    ""Name"": ""Graded Assignment:  Part 1"",

    ""CustomInstructions"": {

        ""Text"": ""Directions:\r\nCOMPLETE the following TestOut Activities\r\n\r\n1.2.10 Practice Questions\r\n1.3.8 Practice Questions\r\n\r\nGo to TestOut to complete the Assignment.""

    }

}]

";

            return json;

        }

    }

​

​

    public class Program

    {

        public static void Main()

        {

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

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

            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;

        }

    }

​