using System;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        var deSerialized = JsonConvert.DeserializeObject<MyModel>("{\"myName\":\"My Name\",\"myPolygon\":{\"type\":\"Polygon\",\"coordinates\":[[[-100.0,45.0],[-98.0,45.0],[-99.0,46.0],[-100.0,45.0]]]}}");

        Console.WriteLine("myName: " + deSerialized.myName);

        Console.WriteLine("myPolygon: " + deSerialized.myPolygon?.type);

    }

}

​

public class MyModel

{

    public string myName { get; set; }

​

    [JsonConverter(typeof(MyPolygonConverter))]

    public Polygon myPolygon { get; set; }

}

​

public class Polygon

{

    public string type { get; set; }

    public double[][][] coordinates { get; set; }

}

​

public class MyPolygonConverter : JsonConverter<Polygon>

{

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

        bool hasExistingValue, JsonSerializer serializer)

    {

        // reader is currently positioned on JsonToken.StartObject, so the Value of the reader is null.

        DumpReaderTokenTypeAndValue(reader);

        Polygon poly = new Polygon();

​

        while (reader.TokenType != JsonToken.EndObject)

        {

            reader.Read();

            DumpReaderTokenTypeAndValue(reader);

            // logic to populate polygon goes here...

        }

​

        return poly;

    }

    private void DumpReaderTokenTypeAndValue(JsonReader reader)

    {

        Console.WriteLine($"token type is {reader.TokenType}, value is {(reader.Value == null ? "null" : reader.Value.ToString())}");

    }

    public override bool CanWrite => false;

    public override void WriteJson(JsonWriter writer, Polygon polygon, JsonSerializer serializer)

    {

        throw new NotImplementedException();

    }

}