MVC & WebAPI “Multiple types were found that match the controller named…”

Question

I have a routing problem with MVC and WebAPI controllers.

The error is:

Multiple types were found that match the controller named 'Log'. This can happen if the route that services this request ('api/{controller}/{action}/{id}') found multiple controllers defined with the same name but differing namespaces, which is not supported. The request for 'Log' has found the following matching controllers: MyNamespace.Controllers.LogController MyNamespace.Controllers.WebAPI.LogController

My routing is simple:

public static void RegisterRoutes(RouteCollection routes)
{
    routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

    routes.MapRoute(
        name: "Default",
        url: "{controller}/{action}/{id}",
        defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
    );
}

I have tried adding an additional route for WebAPI like:

routes.MapHttpRoute(
    name: "API",
    routeTemplate: "api/{controller}/{action}/{id}",
    defaults: new { id = RouteParameter.Optional }
);

Along with adding a namespace for the MVC route:

namespaces: new[] { "MyNamespace.Controllers" }

But I still receive the same error. I cannot see a way to specify the namespace for the WebAPI route.

There is a well-upvoted duplicate but that is specifically about MVC controllers. The answers talk about adding a namespace as above, which has not helped here. In my case the routing to the MVC controller works fine, and it is only the WebAPI controller where I have the problem.

The strange thing is, all my other WebAPI controllers have the same name as MVC controllers but this is the only one where I run into the error.

I'd strongly recommend renaming the controller, in the long run it's just safer and easier to work with anyway. — DavidG
@DavidG that does seem the sensible option going forward. But I'm interested in understanding why this is happening though, particularly when it only affects one controller and other duplicate names are fine. — Owen Pauling
What if you put namespace constraint in the API route? like namespaces: new[] { "MyNamespace.Controllers.WebAPI" }. Your API controllers are still in the namespace of MyNamespace.Controllers if you specify them at the MVC level. — Craig H
@CraigH unless I'm missing something there's no parameter for the namespace in MapHttpRoute (as opposed to MapRoute). — Owen Pauling

melek melek · Accepted Answer · 2019-12-28T08:42:22

If you changed the name of the project, you must delete the files in the bin folder with the old project name.

MVC & WebAPI “Multiple types were found that match the controller named…”

1 Answers