Custom serialization for ExpandoObjects in ASP.NET WebAPI

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Dynamic;
using System.Runtime.Serialization;

namespace Abacus.Relay.Service.Binders
{
    [Serializable]
    public class DynamicSerializable : DynamicObject, ISerializable
    {
        private readonly Dictionary<string, object> dictionary = new Dictionary<string, object>();

        public override bool TrySetMember(SetMemberBinder binder, object value)
        {
            if (!dictionary.ContainsKey(binder.Name))
            {
                dictionary.Add(binder.Name, value);
            }
            else
            {
                dictionary[binder.Name] = value;
            }

            return true;
        }

        public void GetObjectData(SerializationInfo info, StreamingContext context)
        {
            foreach (var kvp in dictionary)
            {
                info.AddValue(kvp.Key, kvp.Value);
            }
        }
    }
}