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/62940751/json-net-how-to-ignore-null-elements-in-array-deserializing-a-json

​

    public class NullFilteringListConverter : JsonConverter

    {

        public override bool CanConvert(Type objectType)

        {

            if (objectType.IsArray || objectType == typeof(string) || objectType.IsPrimitive)

                return false;

            var itemType = objectType.GetListItemType();

            return itemType != null && (!itemType.IsValueType || Nullable.GetUnderlyingType(itemType) != null);

        }

​

        object ReadJsonGeneric<T>(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)

        {

            var list = existingValue as List<T> ?? (List<T>)serializer.ContractResolver.ResolveContract(objectType).DefaultCreator();

            serializer.Populate(reader, list);

            list.RemoveAll(i => i == null);

            return list;

        }

​

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

        {

            if (reader.MoveToContentAndAssert().TokenType == JsonToken.Null)

                return null;

            var itemType = objectType.GetListItemType();

            var method = typeof(NullFilteringListConverter).GetMethod("ReadJsonGeneric", BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public);

            try

            {

                return method.MakeGenericMethod(new[] { itemType }).Invoke(this, new object[] { reader, objectType, existingValue, serializer });

            }

            catch (Exception ex)

            {

                // Wrap the TargetInvocationException in a JsonSerializerException

                throw new JsonSerializationException("Failed to deserialize " + objectType, ex);

            }

        }

​

        public override bool CanWrite => false;

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) => throw new NotImplementedException();

    }

    public static partial class JsonExtensions

    {

        internal static Type GetListItemType(this Type type)

        {

            // Quick reject for performance

            if (type.IsPrimitive || type.IsArray || type == typeof(string))

                return null;

            while (type != null)

            {

                if (type.IsGenericType)

                {

                    var genType = type.GetGenericTypeDefinition();

                    if (genType == typeof(List<>))

                        return type.GetGenericArguments()[0];

                }

                type = type.BaseType;

            }

            return null;

        }

    }

​

    public static partial class JsonExtensions

    {

        public static JsonReader MoveToContentAndAssert(this JsonReader reader)

        {

            if (reader == null)

                throw new ArgumentNullException();

            if (reader.TokenType == JsonToken.None)       // Skip past beginning of stream.

                reader.ReadAndAssert();

            while (reader.TokenType == JsonToken.Comment) // Skip past comments.

                reader.ReadAndAssert();

            return reader;

        }

​

        public static JsonReader ReadAndAssert(this JsonReader reader)

        {

            if (reader == null)

                throw new ArgumentNullException();

            if (!reader.Read())

                throw new JsonReaderException("Unexpected end of JSON stream.");

            return reader;

        }

    }

​

    public class Class1

    {

        public string Variable1 { get; set; }

        public string Variable2 { get; set; }

        public List<ArrayObject> ArrayObject { get; set; }

    }

​

    public class ArrayObject

    {

        public string VariableArray1 { get; set; }

        public string VariableArray2 { get; set; }

    }

​

    class TestClass

    {

        public static void Test()

        {

            var json = GetJson();

            var settings = new JsonSerializerSettings()

            {

                ReferenceLoopHandling = ReferenceLoopHandling.Ignore,

                NullValueHandling = NullValueHandling.Ignore,

                Converters = { new NullFilteringListConverter() },

            };

​

            Class1 class1 = JsonConvert.DeserializeObject<Class1>(json, settings);

​

            Console.WriteLine(class1.ArrayObject == null);

            Console.WriteLine(class1.ArrayObject.Count());

​

            foreach (var item in class1.ArrayObject)

            {

                Console.WriteLine(item.VariableArray1);

                Console.WriteLine(item.VariableArray2);

                Console.WriteLine("#######################");

            }

            Assert.IsTrue(class1.ArrayObject.All(i => i != null));

        }           

        static string GetJson()

        {

            return @"{

    ""Variable1"": ""1"",

    ""Variable2"": ""50000"",

    ""ArrayObject"": /*Some Comment */ [null /*Some Comment */, {}, null, {}]

}";

        }

    }

​

    public class Program

    {

        public static void Main()

        {

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

            Console.WriteLine("{0} version: {1}", typeof(JsonSerializer).Assembly.GetName().Name,  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;

        }

    }

​