url.Action with MvcContrib generates invalid links

Question

In our application we use MvcContrib for generating links with the exception of cross area links where Contrib seems to be not working properly (or we are doing something wrong). In services we have a function that generates a List< ZakladkaModel > which contains url and other properties used in generating tabstrib via custom html helper. That function takes as an argument an id of database object and UrlHelper to help in link creating.

m_service.GenerowanieZakladkiDlaKontrolera_ARCH_Akt(idAktu, new UrlHelper(this.ControllerContext.RequestContext));

Then in the GenerowanieZakladkiDlaKontrolera_ARCH_Akt we have something like this:

model.Add(new ZakladkaModel { Aktywnosc = true, NazwaZakladki = "Akt", Url = "" });
model.Add(new ZakladkaModel { Aktywnosc = true, NazwaZakladki = "Wzmianki", Url = url.Action<Usc.Presentation.Areas.FU_RAU.Controllers.ARCH.ARCH_WzmiankiController>(c => c.Index(idAktu)) });
if (tekstJednolity.StanTekstuJednolitego == "RB" || tekstJednolity.StanTekstuJednolitego == "SW")
{
model.Add(new ZakladkaModel { Aktywnosc = true, NazwaZakladki = "t.j. aktu", Url = url.Action<Usc.Presentation.Areas.FU_RAU.Controllers.ARCH.ARCH_TekstJednolityController>(c => c.Edytuj(tekstJednolity.Id)) });
}
else
{
model.Add(new ZakladkaModel { Aktywnosc = true, NazwaZakladki = "t.j. aktu", Url = url.Action<Usc.Presentation.Areas.FU_RAU.Controllers.ARCH.ARCH_TekstJednolityController>(c => c.Raport(tekstJednolity.Id)) });
}
model.Add(new ZakladkaModel { Aktywnosc = true, NazwaZakladki = "Przypisek 1", Url = url.Action<Usc.Presentation.Areas.FU_RAU.Controllers.ARCH.Przypisek1Controller>(c => c.Index(idAktu)) });
model.Add(new ZakladkaModel { Aktywnosc = true, NazwaZakladki = "Przypisek 2", Url = url.Action<Usc.Presentation.Areas.FU_RAU.Controllers.ARCH.Przypisek2Controller>(c => c.Index(idAktu)) });
model.Add(new ZakladkaModel { Aktywnosc = true, NazwaZakladki = "Przypisek 3", Url = url.Action<Usc.Presentation.Areas.FU_RAU.Controllers.ARCH.Przypisek3Controller>(c => c.Edytuj(idAktu)) });
model.Add(new ZakladkaModel { Aktywnosc = true, NazwaZakladki = "Przypisek 4", Url = url.Action<Usc.Presentation.Areas.FU_RAU.Controllers.ARCH.Przypisek4Controller>(c => c.Edytuj(idAktu)) });

Now the problem is that on some co-workers computers it generates links to actions properly and on some it looks like it takes a ranedom area from our app and tries to make an invalid link. We could use a simple url.Action("action","controler") which works fine on all but we would prefer MvcContrib :). Does anyone have any idea why this occurs? Or can share an alternative?

Answer 1

It seems that LinkBuilder which is used under doesn't use GetVirtualPatchForArea at all which as I read is MVC bug. So i decided to make my own HtmlHelper which uses that method:

 public static string ActionArea<TController>(this HtmlHelper urlHelper, Expression<Action<TController>> expression) where TController : Controller
{
     RouteValueDictionary routeValues = GetRouteValuesFromExpression(expression);
     VirtualPathData vpd = new UrlHelper(urlHelper.ViewContext.RequestContext).RouteCollection.GetVirtualPathForArea(urlHelper.ViewContext.RequestContext, routeValues);
   return (vpd == null) ? null : vpd.VirtualPath;
}

public static string ActionArea<TController>(this UrlHelper urlHelper, Expression<Action<TController>> expression) where TController : Controller
        {
            RouteValueDictionary routeValues = GetRouteValuesFromExpression(expression);
            VirtualPathData vpd = urlHelper.RouteCollection.GetVirtualPathForArea(urlHelper.RequestContext, routeValues);
            return (vpd == null) ? null : vpd.VirtualPath;
        }

public static RouteValueDictionary GetRouteValuesFromExpression<TController>(Expression<Action<TController>> action) where TController : Controller
        {
            if (action == null)
            {
                throw new ArgumentNullException("action");
            }

            MethodCallExpression call = action.Body as MethodCallExpression;
            if (call == null)
            {
                throw new ArgumentException("Akcja nie może być pusta.", "action");
            }

            string controllerName = typeof(TController).Name;
            if (!controllerName.EndsWith("Controller", StringComparison.OrdinalIgnoreCase))
            {
                throw new ArgumentException("Docelowa klasa nie jest kontrolerem.(Nie kończy się na 'Controller')", "action");
            }
            controllerName = controllerName.Substring(0, controllerName.Length - "Controller".Length);
            if (controllerName.Length == 0)
            {
                throw new ArgumentException("Nie można przejść do kontrolera.", "action");
            }

            // TODO: How do we know that this method is even web callable?
            //      For now, we just let the call itself throw an exception.

            string actionName = GetTargetActionName(call.Method);

            var rvd = new RouteValueDictionary();
            rvd.Add("Controller", controllerName);
            rvd.Add("Action", actionName);

            var namespaceNazwa = typeof(TController).Namespace;

            if(namespaceNazwa.Contains("Areas."))
            {
                int index = namespaceNazwa.IndexOf('.',namespaceNazwa.IndexOf("Areas."));
                string nazwaArea = namespaceNazwa.Substring(namespaceNazwa.IndexOf("Areas.") + 6, index - namespaceNazwa.IndexOf("Areas.") + 1);
                if (!String.IsNullOrEmpty(nazwaArea))
                {
                    rvd.Add("Area", nazwaArea);
                }
            }

            //var typ = typeof(TController).GetCustomAttributes(typeof(ActionLinkAreaAttribute), true /* inherit */).FirstOrDefault();
            /*ActionLinkAreaAttribute areaAttr = typ as ActionLinkAreaAttribute;
            if (areaAttr != null)
            {
                string areaName = areaAttr.Area;
                rvd.Add("Area", areaName);
            }*/

            AddParameterValuesFromExpressionToDictionary(rvd, call);
            return rvd;
        }


private static string GetTargetActionName(MethodInfo methodInfo)
        {
            string methodName = methodInfo.Name;

            // do we know this not to be an action?
            if (methodInfo.IsDefined(typeof(NonActionAttribute), true /* inherit */))
            {
                throw new InvalidOperationException(String.Format(CultureInfo.CurrentUICulture,
                    "Nie można wywoływać metod innych niż akcje.", methodName));
            }

            // has this been renamed?
            ActionNameAttribute nameAttr = methodInfo.GetCustomAttributes(typeof(ActionNameAttribute), true /* inherit */).OfType<ActionNameAttribute>().FirstOrDefault();
            if (nameAttr != null)
            {
                return nameAttr.Name;
            }

            // targeting an async action?
            if (methodInfo.DeclaringType.IsSubclassOf(typeof(AsyncController)))
            {
                if (methodName.EndsWith("Async", StringComparison.OrdinalIgnoreCase))
                {
                    return methodName.Substring(0, methodName.Length - "Async".Length);
                }
                if (methodName.EndsWith("Completed", StringComparison.OrdinalIgnoreCase))
                {
                    throw new InvalidOperationException(String.Format(CultureInfo.CurrentUICulture,
                       "Nie można wywoływać kompletnych metod.", methodName));
                }
            }

            // fallback
            return methodName;
        }

static void AddParameterValuesFromExpressionToDictionary(RouteValueDictionary rvd, MethodCallExpression call)
        {
            ParameterInfo[] parameters = call.Method.GetParameters();

            if (parameters.Length > 0)
            {
                for (int i = 0; i < parameters.Length; i++)
                {
                    Expression arg = call.Arguments[i];
                    object value = null;
                    ConstantExpression ce = arg as ConstantExpression;
                    if (ce != null)
                    {
                        // If argument is a constant expression, just get the value
                        value = ce.Value;
                    }
                    else
                    {
                        value = CachedExpressionCompiler.Evaluate(arg);
                    }
                    rvd.Add(parameters[i].Name, value);
                }
            }
        }

Hope this helps people with similiar problems. Some of the code above i got from mvc2-rtm-sources modified to my needs http://aspnet.codeplex.com/releases/view/41742