Best place to set CurrentCulture for multilingual ASP.NET MVC web applications

Question

For multilingual ASP.NET MVC 3 web application, I am determining the Thread.CurrentThread.CurrentCulture and Thread.CurrentThread.CurrentUICulture on the controller factory as follows:

public class MyControllerFactory : DefaultControllerFactory {

    protected override IController GetControllerInstance(System.Web.Routing.RequestContext requestContext, Type controllerType) {

        //Get the {language} parameter in the RouteData
        string UILanguage;
        if (requestContext.RouteData.Values["language"] == null)
            UILanguage = "tr";
        else
            UILanguage = requestContext.RouteData.Values["language"].ToString();

        //Get the culture info of the language code
        CultureInfo culture = CultureInfo.CreateSpecificCulture(UILanguage);
        Thread.CurrentThread.CurrentCulture = culture;
        Thread.CurrentThread.CurrentUICulture = culture;

        return base.GetControllerInstance(requestContext, controllerType);
    }

}

The above code is nearly a year old now! So, I open for suggestions.

And I register this on the Global.asax file like:

ControllerBuilder.Current.SetControllerFactory(new MyControllerFactory());

This is working good but I am not sure if it is the best practice and best place to do this type of action.

I haven't dug into the main role of ControllerFactory and I am unable to compare it against ActionFilterAttribute.

What do you think about the best place to do this type of action?

Answer 1

I used a global ActionFilter for this, but recently I realized, that setting the current culture in the OnActionExecuting method is too late in some cases. For example, when model after POST request comes to the controller, ASP.NET MVC creates a metadata for model. It occurs before any actions get executed. As a result, DisplayName attribute values, and other Data Annotations stuff are handled using the default culture at this point.

Eventually I've moved setting the current culture to the custom IControllerActivator implementation, and it works like a charm. I suppose it's almost the same from the request lifecycle perspective to host this logic in the custom controller factory, like you have today. It's much more reliable, than usage of global ActionFilter.

CultureAwareControllerActivator.cs:

public class CultureAwareControllerActivator: IControllerActivator
{
    public IController Create(RequestContext requestContext, Type controllerType)
    {
        //Get the {language} parameter in the RouteData
        string language = requestContext.RouteData.Values["language"] == null ?
            "tr" : requestContext.RouteData.Values["language"].ToString();

        //Get the culture info of the language code
        CultureInfo culture = CultureInfo.GetCultureInfo(language);
        Thread.CurrentThread.CurrentCulture = culture;
        Thread.CurrentThread.CurrentUICulture = culture;

        return DependencyResolver.Current.GetService(controllerType) as IController;
    }
}

Global.asax.cs:

public class MvcApplication : System.Web.HttpApplication
{
    protected void Application_Start()
    {
        ...
        ControllerBuilder.Current.SetControllerFactory(new DefaultControllerFactory(new CultureAwareControllerActivator()));
    }
}