Dependency Injection with Ninject and Filter attribute for asp.net mvc

Question

I'm writing a custom Authorization Filter for asp.net mvc 3. I need to inject a userservice into the class but I have no idea how to do this.

public class AuthorizeAttribute : FilterAttribute, IAuthorizationFilter
{
    private IUserService userService;
    private string[] roles;

    public AuthorizeAttribute(params string[] roles)
    {
        this.roles = roles;
    }

    public void OnAuthorization(AuthorizationContext filterContext)
    {
        throw new NotImplementedException();
    }
}

I'm using ninject for dependency injection. I do not want to use a Factory or service locator pattern.

My bindings look like this in the global.acsx:

    internal class SiteModule : NinjectModule
    {
        public override void Load()
        {
            Bind<IUserService>().To<UserService>();
        }
    }

Answer 1

See this answer:

Custom Authorization MVC 3 and Ninject IoC

If you want to use constructor injection then you need to create an attribute and a filter.

///marker attribute
public class MyAuthorizeAttribute : FilterAttribute { }

//filter
public class MyAuthorizeFilter : IAuthorizationFilter
{
      private readonly IUserService _userService;
      public MyAuthorizeFilter(IUserService userService)
      {
          _userService = userService;
      }

      public void OnAuthorization(AuthorizationContext filterContext)
      {
          var validUser = _userService.CheckIsValid();

          if (!validUser)
          {
              filterContext.Result = new RedirectToRouteResult(new RouteValueDictionary { { "action", "AccessDenied" }, { "controller", "Error" } });
          }
      }
}

Binding:

this.BindFilter<MyAuthorizeFilter>(System.Web.Mvc.FilterScope.Controller, 0).WhenControllerHas<MyAuthorizeAttribute>();

Controller:

[MyAuthorizeAttribute]
public class YourController : Controller
{

}

HTH...