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/57152212/creating-a-custom-converter-to-write-json-as-a-dictionarystring-iobject-from

​

    public class PDItem : IDictionaryObject<List<IItem>>

    {

        [JsonProperty]

        public string Key { get; set; }

​

        [JsonProperty]

        public List<IItem> Value { get; set; }

    }

​

    public interface IDictionaryObject<T>

    {

        string Key { get; set; }

        T Value { get; set; }

    }

​

    [JsonConverter(typeof(IItemConverter))]

    public interface IItem: IElement

    {

    }

​

    [JsonConverter(typeof(ElementConverter))]

    public interface IElement

    {

        string elementType { get; }

    }

​

    public class ElementConverter : JsonCreationConverter<IElement>

    {

        protected override IElement Create(Type objectType, JObject jObject)

        {

            //TODO:  Add objects to ElementConverter as they come online.

            switch (jObject["elementType"].Value<string>())

            {

                case ElementTypeDescriptions.FirstType:

                    return new FirstType();

                case ElementTypeDescriptions.SecondType:

                    return new SecondType();

                case ElementTypeDescriptions.ThirdType:

                    return new ThirdType();

                case ElementTypeDescriptions.FourthType:

                case ElementTypeDescriptions.FifthType:

                default:

                    throw new NotImplementedException("This object type is not yet implemented.");

            }

        }

    }

​

    public class PDItemConverter: JsonConverter<PDItem>

    {

        public override void WriteJson(JsonWriter writer, PDItem value, JsonSerializer serializer)

        {

            /// THIS CODE TO BE WRITTEN TO ANSWER THE QUESTION

            /// DO STUFF

            throw new NotImplementedException("THIS CODE TO BE WRITTEN TO ANSWER THE QUESTION");

        }

​

        public override PDItem ReadJson(JsonReader reader, Type objectType, PDItem existingValue,

            bool hasExistingValue, JsonSerializer serializer)

        {

            /// THIS CODE TO BE WRITTEN TO ANSWER THE QUESTION

            /// DO STUFF

            throw new NotImplementedException("THIS CODE TO BE WRITTEN TO ANSWER THE QUESTION");

        }

    }

​

    public abstract class JsonCreationConverter<T> : JsonConverter

    {

        protected abstract T Create(Type objectType, JObject jObject);

​

        public override bool CanConvert(Type objectType)

        {

            return typeof(T) == objectType;

        }

​

        public override object ReadJson(JsonReader reader, Type objectType,

            object existingValue, JsonSerializer serializer)

        {

            try

            {

                var jObject = JObject.Load(reader);

                var target = Create(objectType, jObject);

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

                return target;

            }

            catch (JsonReaderException)

            {

                return null;

            }

        }

​

        public override void WriteJson(JsonWriter writer, object value,

            JsonSerializer serializer)

        {

            throw new NotImplementedException();

        }

    }

​

    class TestClass

    {

        public static void Test()

        {

            var json = GetJson();

            var item = JsonConvert.DeserializeObject<PDItem>(json);

            var json2 = JsonConvert.SerializeObject(item, Formatting.Indented);

            Console.WriteLine(json2);

        }   

        static string GetJson()

        {

            var json = @"{

    ""checked"": [

            {

                ""elementType"": ""input"",

                ""inputType"": ""checkbox"",

                ""name"": ""another_checkbox"",

                ""label"": ""Another checkbox"",

                ""checked"": true

            }

    ]

}

";

            return json;

        }

    }

​

    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;

            }

        }

    }

​