using System;

using System.Collections.Generic;

using System.Linq;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

​

namespace StackOverflow

{

    class Program

    {

        static void Main(string[] args)

        {

            List<NamePair> namePairs = new List<NamePair>

            {

                new NamePair

                {

                    Name = "chris",

                    Surname = "green"

                },

                new NamePair

                {

                    Name = "albert",

                    Surname = "red"

                }

            };

​

            var settings = new JsonSerializerSettings();

            settings.Converters.Add(new NamePairConverter());

            settings.Formatting = Formatting.Indented;

​

            var json = JsonConvert.SerializeObject(new {entities = namePairs}, settings);

            Console.WriteLine(json);

​

            var json2 = JsonConvert.SerializeObject(new Dictionary<string, string> {{"John", "Doe"}, {"Alex", "Steelflex"}},

                Formatting.Indented);

            Console.WriteLine(json2);

​

            Console.ReadLine();

        }

    }

​

    struct NamePair

    {

        public string Name { get; set; }

​

        public string Surname { get; set; }

    }

​

    class NamePairConverter : JsonConverter

    {

        public override object ReadJson(

            JsonReader reader,

            Type objectType,

            object existingValue,

            JsonSerializer serializer

        )

        {

            var obj = (JObject)JToken.ReadFrom(reader);

​

​

            JProperty property = obj.Properties().FirstOrDefault();

​

            return new NamePair

            {

                Surname = property.Name,

                Name = property.Value<string>()

            };

        }

​

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

        {

            var namePair = (NamePair) value;

            var obj = new JObject

            {

                [namePair.Surname] = namePair.Name

            };

            obj.WriteTo(writer);

        }

​

        public override bool CanConvert(Type t)

        {

            return typeof(NamePair).IsAssignableFrom(t);

        }

​

        public override bool CanRead => true;

    }

}