ASP.NET MVC Custom Error page (StatusCode 404 throws a 500)

Question

I've got customErrors set in my web.config

<customErrors mode="On" defaultRedirect="/Error/GeneralError">
    <error statusCode="404" redirect="/Error/NotFound"/>
</customErrors>

This works fine locally. A 404 throws a 404. On the shared hosting it throws up the standard server 404 page unless I specifically set 404 to point to /Error/NotFound. That's fine. Now it will show the custom 404 page except the response status code is 200. So if I try to throw Response.StatusCode = 404; in my NotFound action in ErrorController like this:

public class ErrorController : Controller
{
    public ActionResult NotFound()
    {
        Response.StatusCode = 404;
        return View();
    }
}

the server throws a status code 500 Internal Server Error but my GeneralError page doesn't show, just a blank white page with no source.

I've tried many different combinations but I can't seem to find how to make it show my custom 404 page along with a 404 response.

Any ideas?

Answer 1

I found out some interesting information here: http://blog.angrypets.com/2008/03/responsetryskip.html

Response.TrySkipIisCustomErrors = true; 

Setting TrySkipIisCustomErrors to true after the Response.StatusCode = 404; takes care of the issue.

Answer 2

Don't use a customErrors element (except to turn mode="On" for local testing). Instead, add an Application_EndRequest method to your MvcApplication per Marco's Better-Than-Unicorns MVC 404 Answer.