C# WebAPI and NotFound with message in MVC .NET 4.5

Usually,WEBAPI should return correct HTML status code ( read also https://damienfremont.com/2017/11/23/rest-api-maturity-levels-from-0-to-5/ ) . Let’s say we are saving an entity  – the OK result could return a meaningful message. How about querying for an id that you cannot find ? Easy: NotFound :  .But –the NotFound does NOT show an message. How a client can make a difference between the fact that the entity is not found for a specific id and the fact that,maybe,the whole site is not deployed / a route does not exists  ? What we need is a NotFound with a specific message. ( In .NET Core we have NotFoundObjectResult )

I have found 2 solutions: one complicated and one simple.

The complicated one:

var err = Request.CreateErrorResponse(
HttpStatusCode.NotFound,
new HttpError("my message”)
);
return new ResponseMessageResult(err);

The simple one

//this is for APIController only,not usual controller in .NET 4.5
return Content(HttpStatusCode.NotFound,"my message");

Enjoy!