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/62265721/problem-crash-with-newtonsoft-json-deserializing

​

    class TestClass

    {

        public static void Test()

        {

            var ListaEntes = new List< Ente >();

            ListaEntes.Add( new Enemy( 10 ) );

            ListaEntes.Add( new Enemy( 20 ) );

​

            JsonSerializer serializer = new JsonSerializer();

            serializer.TypeNameHandling = TypeNameHandling.Objects;

            serializer.Formatting = Formatting.Indented;

​

            string folder = "archivoPrueba.dat";

            using (StreamWriter sw = new StreamWriter( @folder ))

            using (JsonWriter writer = new JsonTextWriter( sw ))

            {

               serializer.Serialize( writer, ListaEntes );

            }

            ListaEntes.Clear();

            Console.WriteLine(File.ReadAllText(folder));

​

            using (StreamReader sr = new StreamReader( @folder ))

            using (JsonReader reader = new JsonTextReader( sr ))

            {

                JsonEnteConverter jsonEnteConverter = new JsonEnteConverter();

​

                ListaEntes = ( List< Ente > ) jsonEnteConverter.ReadJson( reader, null, null, serializer );

            }

        }   

    }

​

    public class        Ente

    {

        public string tipo;

        public Animator animator;

    }

​

    public class        Enemy : Ente

    {

        public          Enemy()

        {

            animator = new Animator( this );

        }

​

        public          Enemy( int pVar )

        {

            tipo = "enemigo";

        }

    }

​

    public class        Animator

    {

        Ente father;

​

        public          Animator( Enemy pEnemy )

        {

            father = pEnemy;

        }

    }

​

    public class        JsonEnteConverter : Newtonsoft.Json.Converters.CustomCreationConverter< Ente >

    {

        public override Ente Create( Type objectType )

        {

            throw new NotImplementedException();

        }

​

        public          Ente Create( JObject jObject )

        {

            string type = jObject.Property( "tipo" ).ToString(); //get property Type from your json

​

            switch ( type )

            {

                case "enemigo":

                    return new Enemy();

            }

            throw new ApplicationException(String.Format("Type not found", type));

        }

​

        public override object ReadJson( JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer )

        {

            JObject jObject = JObject.Load( reader );

            var targetObject = Create( jObject );

            serializer.Populate( jObject.CreateReader(), targetObject );

            return targetObject;

        }

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: " + Environment.Version);

            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;

            }

        }

    }

​