using System;

using System.Collections.Generic;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using System.Linq;

using System.Collections;

​

public class Program

{

    public static void Main()

    {

        var bar = new Foo();

        bar.Boolean = true;

        bar.List = new List<Bar>() { 

           new Bar(){ Value = "Foo1" }, 

           new Bar(){ Value = "Bar2" },

           new Bar(){ Value = "Foo3" } 

        };

        var json = JsonConvert.SerializeObject(bar, Formatting.Indented);

        Console.WriteLine(json);

    }

    public class Foo

    {

        public bool Boolean;

​

        [JsonIgnore]

        public List<Bar> List;

​

        [JsonExtensionData]

        public Dictionary<string, JToken> Values

        {

            get

            {

                return List.Select((v, i) => new KeyValuePair<string, JToken>($"Property{i + 1}", JValue.CreateString(v.Value))).ToDictionary(kvp => kvp.Key, kvp => kvp.Value);

            }

        }

    }

​

    public class Bar{

       public string Value{ get; set; }

    }

}