WebAPI Exception Handling

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using System.Web.Http;
using System.Web.Http.Filters;
using Newtonsoft.Json;

namespace MvcApplication2.Controllers
{
    public class FooController : ApiController
    {
        [HttpPost]
        [ExcHand]
        public async Task<GetFooResponse> GetFoo(GetFooRequest request)
        {
            throw new ApplicationException("Fail - you suck");
            return new GetFooResponse
            {
                Foo = new Foo { Message = "Hello " + request.Name }
            };
        }
    }

    public class Foo
    {
        public string Message { get; set; }
    }

    public class GetFooRequest
    {
        public string Name { get; set; }
    }

    public class BaseResponse
    {
        public string ErrorMessage { get; set; }
    }

    public class GetFooResponse
        : BaseResponse
    {
        public Foo Foo { get; set; }
    }

    public class ExcHandAttribute : ExceptionFilterAttribute
    {
        public override void OnException(HttpActionExecutedContext actionExecutedContext)
        {
            var responseObject = (BaseResponse)Activator.CreateInstance(actionExecutedContext.ActionContext.ActionDescriptor.ReturnType);
            responseObject.ErrorMessage = actionExecutedContext.Exception.ToString();
            var msg = new HttpResponseMessage(HttpStatusCode.OK)
                {
                    Content = new StringContent(JsonConvert.SerializeObject(responseObject))
                };
            actionExecutedContext.Response = msg;
        }
    }
}