Custom serialization for ExpandoObjects in ASP.NET WebAPI

using System.Net.Http;
using System.Web.Http.Filters;

namespace WebAPIProject.Filters
{
    public class ExceptionHandlingAttribute : ExceptionFilterAttribute
    {
        public override void OnException(HttpActionExecutedContext context)
        {
            //Log Critical errors

            var httpResponseMessage = new HttpResponseMessage() { ReasonPhrase = context.Exception == null ? string.Empty : context.Exception.Message };
            context.Response = httpResponseMessage;

            //throw new HttpResponseException(httpResponseMessage);
        }
    }
}