using System;

using Newtonsoft.Json;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        Example1AsString();

        Example2AsObject();

    }

    public static void Example1AsString ()

    {

        var zoopla = new ZooplaTest();      

        zoopla.CouncilTaxBand = "A";

        var serializerSettings = new JsonSerializerSettings

        {

            Converters = new List<JsonConverter>

            {

                new CouncilTaxBandStringConverter(),

                new CouncilTaxBandObjectConverter()

            }

        };

​

        var json = JsonConvert.SerializeObject(zoopla, serializerSettings);

        Console.WriteLine("EXAMPLE 1: string");

        Console.WriteLine(json);        

    }

    public static void Example2AsObject ()

    {

        var zoopla = new ZooplaTest();

        zoopla.CouncilTaxBand = new CouncilTaxBandObject

        {

            Exempt = "I am exempt"

        };

        var serializerSettings = new JsonSerializerSettings

        {

            Converters = new List<JsonConverter>

            {

                new CouncilTaxBandStringConverter(),

                new CouncilTaxBandObjectConverter()

            }

        };

​

        var json = JsonConvert.SerializeObject(zoopla, serializerSettings);

        Console.WriteLine("EXAMPLE 2: object");

        Console.WriteLine(json);        

    }

    public class ZooplaTest

    {

        public object CouncilTaxBand { get; set; }  

    }   

    public class CouncilTaxBandStringConverter : JsonConverter

    {

        public override bool CanRead { get { return false; } }

​

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

        {

            writer.WriteValue(value);

        }

​

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

        {

            throw new NotImplementedException();

        }

​

        public override bool CanConvert(Type objectType)

        {

            return objectType == typeof(string);

        }

    }

​

    public class CouncilTaxBandObjectConverter : JsonConverter

    {

        public override bool CanRead { get { return false; } }

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

        {

            var bandObject = (CouncilTaxBandObject)value;

​

            writer.WriteStartObject();

​

            if (!string.IsNullOrEmpty(bandObject.Exempt))

            {

                writer.WritePropertyName("exempt");

                writer.WriteValue(bandObject.Exempt);

            }

            else if (!string.IsNullOrEmpty(bandObject.NotYetKnown))

            {

                writer.WritePropertyName("not_yet_known");

                writer.WriteValue(bandObject.NotYetKnown);

            }

​

            writer.WriteEndObject();

        }

​

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

        {

            throw new NotImplementedException();

        }

​

        public override bool CanConvert(Type objectType)

        {

            return objectType == typeof(CouncilTaxBandObject);

        }

    }

​

    public class CouncilTaxBandObject

    {

        public string Exempt { get; set; }

        public string NotYetKnown { get; set; }

    }

}