Return Custom HTTP Status Code from WebAPI 2 endpoint

Question

I'm working on a service in WebAPI 2, and the endpoint currently returns an IHttpActionResult. I'd like to return a status code 422, but since it's not in the HttpStatusCode enumeration, I'm at a loss as to how it would be sent, since all of the constructors require a parameter of HttpStatusCode

As it stands now, I'm returning BadResult(message), but returning a 422 + message would be more descriptive and useful for my clients. Any ideas?

Answer 1

According to C# specification:

The set of values that an enum type can take on is not limited by its enum members. In particular, any value of the underlying type of an enum can be cast to the enum type and is a distinct valid value of that enum type

Therefore you can cast status code 422 to HttpStatusCode.

Example controller:

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

namespace CompanyName.Controllers.Api
{
    [RoutePrefix("services/noop")]
    [AllowAnonymous]
    public class NoOpController : ApiController
    {
        [Route]
        [HttpGet]
        public IHttpActionResult GetNoop()
        {
            return new System.Web.Http.Results.ResponseMessageResult(
                Request.CreateErrorResponse(
                    (HttpStatusCode)422,
                    new HttpError("Something goes wrong")
                )
            );
        }
    }
}