Question

I have an ASP.NET MVC 3 application (in IIS 7.5) with a portable area. When I host the application consuming the portable area in a web site my routing works perfectly e.g.

http://localhost:9001/Clearance/Home/Search (this works)

However, when hosting in a virtual directory e.g.

http://localhost/Acme.Risks.Clearance.Web.Area.TestUI/Clearance/Home/Search (this does not work)

I get the following error:

Multiple types were found that match the controller named ‘Home’. This can happen if the route that services this request (‘Clearance/{controller}/{action}’) does not specify namespaces to search for a controller that matches the request. If this is the case, register this route by calling an overload of the ‘MapRoute’ method that takes a ‘namespaces’ parameter.

I don’t understand why, I am specifying namespaces it works fine when running in a web site.

Here is my portable area registration:

    public override void RegisterArea(AreaRegistrationContext context, IApplicationBus bus)
    {
        if (context == null)
        {
            throw new ArgumentNullException("context");
        }

        base.RegisterArea(context, bus);
        context.MapRoute(
            RouteName.ClearanceAreaDefault, 
            this.AreaName + "/{controller}/{action}/{id}", 
            new { controller = "Home", action = "Search", id = UrlParameter.Optional },
            new[] { typeof(HomeController).Namespace });
    }

Here is the Global.asax for the web application in a virtual directory (does not work):

    public static void RegisterRoutes(RouteCollection routes)
    {
        routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
        routes.MapRoute(
            "Default",
            "{controller}/{action}/{id}",
            new { controller = "Home", action = "Index", id = UrlParameter.Optional },
            new[] { typeof(HomeController).Namespace });
    }

Here is the Global.asax for the web application in a web site (does work):

    public static void RegisterRoutes(RouteCollection routes)
    {
        routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
        routes.MapRoute(
            "Default",
            "{controller}/{action}/{id}",
            new { controller = "Home", action = "Index", id = UrlParameter.Optional },
            new[] { "Acme.Risks.Web.UI.Controllers" });
    }

I have used Phil Haack’s “RouteDebugger” (http://nuget.org/packages/routedebugger) and the route debug information on both requests is identical.

Does anyone know why this is happening?

Thanks,

Callum

Answer 1

This was down to the namespace used in the data context for MVC.

My web area assembly is “Acme.Risks.Clearance.Web.Area”.

My web site assembly is “Acme.Risks.Web.UI” (working).

My web area test UI assembly is “Acme.Risks.Clearance.Web.Area.TestUI” (not working).

The namespace used in the data context was “Acme.Risks.Clearance.Web.Area*”, so in the case of the web area test UI the wildcard caused two matches. So even though the routing information was identical, ASP.NET MVC could not decide which was the right assembly because there were duplicate matches.