This blog post is about changing the DefaultControllerFactory to a custom one to allow constructor dependency injection. In this post I use Structuremap, CommonServiceLocator and I use a slightly changed version of the CommonServiceLocator.StructureMapAdatpter.

The DefaultControllerFactory needs a constructor without any input parameters. I want to get rid of dependencies in my code, so I put all my interface dependencies in the constructor and want to use structuremap to handle this for me. I have used this in a semi-large project, but in this blog post I will use an example with only one dependency and only one page.

Lets get started:

I start by creating a new ASP.NET MVC project. I then delete all controllers and views except for my home controller and my index view.

Then I add a Tools folder and a PersonRepository class in my new folder. This only has a default constructor and a get method that returns a Person, a simple object with only a name Property. I also extract an interface from PersonRepository called IPersonRepository.

In my homecontroller I create a constructor that takes a Ipersonrepository as a parameter. This is my HomeController now:

using System.Web.Mvc;
using DIControllerFactoryExample.Tools;

namespace DIControllerFactoryExample.Controllers
{

    public class HomeController : Controller
    {
        private readonly IPersonRepository personRepository;

        public HomeController(IPersonRepository personRepository)
        {
            this.personRepository = personRepository;
        }

        public ActionResult Index()
        {
            var personid = 1;
            ViewData.Model = personRepository.Get(personid);

            return View();
        }
    }
}

I compile, run and get a: "No parameterless constructor defined for this object." exception. Just as planned.
Now, the fun begins. Getting this to work.

I start by adding a solution folder called Lib, and adding StructureMap.dll and Microsoft.Practices.ServiceLocation.dll and reference them in the solution. These can be found at the locations in the top of this blog post.

Then I add 3 new files to my Tools folder.
StructureMapServiceLocator.cs, DefaultStructureMapRegistry.cs, CommonServiceLocatorControllerFactory.cs

These files look like this:

using StructureMap.Configuration.DSL;

namespace DIControllerFactoryExample.Tools
{
    public class DefaultStructureMapRegistry : Registry
    {
        public DefaultStructureMapRegistry()
        {
            ForRequestedType<IPersonRepository>().TheDefaultIsConcreteType
                <PersonRepository>();
        }
    }
}
using System;
using System.Collections.Generic;
using Microsoft.Practices.ServiceLocation;
using StructureMap;

namespace DIControllerFactoryExample.Tools
{
    public class StructureMapServiceLocator : ServiceLocatorImplBase
    {
        private IContainer container;

        public StructureMapServiceLocator(IContainer container)
        {
            this.container = container;
        }

        protected override object DoGetInstance(Type serviceType, string key)
        {
            return string.IsNullOrEmpty(key) ? container.GetInstance(serviceType) : container.GetInstance(serviceType, key);
        }

        protected override IEnumerable<object> DoGetAllInstances(Type serviceType)
        {
            foreach (object obj in container.GetAllInstances(serviceType))
            {
                yield return obj;
            }
        }
    }
}

using System;
using System.Web.Mvc;
using Microsoft.Practices.ServiceLocation;

namespace DIControllerFactoryExample.Tools
{
    public class StructureMapServiceLocatorControllerFactory : DefaultControllerFactory
    {
        protected override IController GetControllerInstance(Type controllerType)
        {
            var controller = ServiceLocator.Current.GetInstance(controllerType) as Controller;
            return controller;
        }
    }
}

I also add the following to the Application_Start method in my Global.asax.cs:

var registry = new DefaultStructureMapRegistry();
var container = new Container(registry);
ServiceLocator.SetLocatorProvider(() => new StructureMapServiceLocator(container));
var locator = new StructureMapServiceLocatorControllerFactory();
ControllerBuilder.Current.SetControllerFactory(locator);

I compile, reload and everything works. That's is. Good luck;)

EDIT: Did a small fix in the code i global.asax, check out this post

The full Visual Studio solution can be downloaded here:

DIControllerFactoryExample.zip (463.5 KB)

I have recently been working on a project where we reimplement an old web application with a new one. Since there has been an page on the same address before, there are also some old applications in other places linking to pages on the old site. For instance, the login.aspx file is linked to in a lot of places.

I will in my example use a link to the page login.aspx in my solution.

To get these links to work, I had (as far as I'm aware of) two options. To make a login.aspx and redirect in this file and add login.aspx to global.asax IgnoreRoute, or to map a new route in global.asax and redirect to my new login. The latter is the solution i went for.

To accomplish this all I had to do was to add the following to RegisterRoutes method in global asax:

routes.MapRoute("Handle login", "login.aspx", new { controller = "Login", action = "Index", id = "" });

Very easy, and now, every request for http://myapp/login.aspx is handled by http://myapp/login/index/