Tutorial :Why is my Castle Windsor controller factory's GetControllerInstance() being called with a null value?



Question:

I am using Castle Windsor to manage controller instances (among other things). My controller factory looks like this:

public class WindsorControllerFactory : DefaultControllerFactory      {          private WindsorContainer _container;            public WindsorControllerFactory()          {              _container = new WindsorContainer(new XmlInterpreter());                var controllerTypes = from t in Assembly.GetExecutingAssembly().GetTypes()                                    where typeof(Controller).IsAssignableFrom(t)                                    select t;                foreach (Type t in controllerTypes)              {                  _container.AddComponentLifeStyle(t.FullName, t, LifestyleType.Transient);              }          }            protected override IController GetControllerInstance(Type controllerType)          {              return (IController)_container.Resolve(controllerType); // ArgumentNullException is thrown here          }  

When I start up my ASP.Net MVC application and try to go to "/" (or another path), I get an ArgumentNullException. I put a break point on entry of the GetControllerInstance and found that it's called once with my HomeController, then a second time with null (which is when the exception is thrown). Why is it being called again?

Should I change the method to something like this:

protected override IController GetControllerInstance(Type controllerType)  {      if (controllerType == null)          return null;        return (IController)_container.Resolve(controllerType);  }  


Solution:1

It turns out that the second request was the MVC framework trying to find a script I included in the Site.Master. The path did not exist, so I guess it tried to resolve a controller (that matched /Scripts/sitescripts.js). I changed the method to this:

protected override IController GetControllerInstance(Type controllerType)  {      if (controllerType != null)      {         return (IController)_container.Resolve(controllerType);      }      else      {         return base.GetControllerInstance(controllerType);      }  }  

And an exception with an understandable message was thrown.


Solution:2

Had this problem when following the Pro ASP.NET MVC Framework book, added

routes.IgnoreRoute("favicon.ico");

to the routes in the global.asax.cs file and it works. See more here: serving favicon.


Solution:3

regarding registration of all the controllers you'd usually do it like this:

container.Register(     AllTypes.FromThisAssembly()        .BasedOn<IController>()        .Configure(c => c.Lifestyle.Transient)  );  

See the documentation for more explanation of the API.


Solution:4

Very late addition: The step-by-step tutorial at the windsor site seems good. It breaks down the creation of a controller and how it's loaded into the factory. It also covers the "favicon.ico" noise.

http://docs.castleproject.org/(S(0jvahybwt45sgwzwirpa3455))/Windsor.Windsor-tutorial-part-one-getting-Windsor.ashx


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