How to inject dependency into MVC 5 global filter using Autofac

Question

I am registering a global filter in MVC5 that takes a dependency on a Migration class:

public static void RegisterGlobalFilters(GlobalFilterCollection filters)
{
   filters.Add(new OfflineActionFilter(new Migration("connectionstring"));
}

I am using Autofac to inject dependencies into my controllers and I would prefer to use dependency injection here too. And I would prefer not to use the service locator (anti)-pattern. How to do this? Property injection in the OfflineActionFilter perhaps? But how?

Answer 1

I found the solution in the documentation under enable property injection for action filters:

First remove call to filters.Add in the RegisterGlobalFilters method and use Autofac's MVC integration to register the filter instead:

builder.RegisterFilterProvider();
builder.Register(c => new OfflineActionFilter()) //parameterless constructor
       .AsActionFilterFor<Controller>()
       .PropertiesAutowired() //using property injection here
       .InstancePerRequest();

Interestingly, while the title of the section in the documentation might make you think we could only use property injection, I found that it also worked with constructor injection (so I went with this solution instead):

builder.RegisterFilterProvider();    
builder.Register(c => 
         new OfflineActionFilter(c.Resolve<Migration>()))//constructor with parameter
       .AsActionFilterFor<Controller>()
       .InstancePerRequest();