using System;

using System.Collections.Generic;

using System.Reflection;

using Newtonsoft.Json;

using Newtonsoft.Json.Serialization;

public class Program

{

    public static void Main()

    {

        List<Bar> bars = new List<Bar>

        {

            new Bar

            {

                SomeFoo = new Foo

                {

                    Enabled = false,

                    Name = "Some Foo 1"

                },

                OtherFoo = new Foo

                {

                    Enabled = true,

                    Name = "Another Foo 1"

                }

            },

            new Bar

            {

                SomeFoo = new Foo

                {

                    Enabled = true,

                    Name = "Some Foo 2"

                },

                OtherFoo = new Foo

                {

                    Enabled = false,

                    Name = "Another Foo 2"

                }

            },

        };

        JsonSerializerSettings settings = new JsonSerializerSettings

        {

            ContractResolver = new CustomResolver(),

            Formatting = Formatting.Indented

        };

        string json = JsonConvert.SerializeObject(bars, settings);

        Console.WriteLine(json);

    }

}

​

class CustomResolver : DefaultContractResolver

{

    protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)

    {

        IList<JsonProperty> properties = base.CreateProperties(type, memberSerialization);

        foreach (JsonProperty prop in properties)

        {

            if (prop.PropertyType == typeof(Foo))

            {

                prop.ShouldSerialize = obj => 

                {

                    Foo foo = (Foo)type.GetProperty(prop.PropertyName).GetValue(obj);

                    return foo.Enabled;

                };

            }

        }

        return properties;

    }

}

​

public class Foo

{

    public bool Enabled { get; set; }

    public string Name { get; set; }

}

​

public class Bar

{

    public Foo SomeFoo { get; set; }

    public Foo OtherFoo { get; set; }

}

​