MVC Web API not working with Autofac Integration

问题:

I used the MVC integration from autofac like this:

...
var container = builder.Build();
DependencyResolver.SetResolver(new AutofacDependencyResolver(container));

But now I want to recreate the solution with the new Web Api RTM. And I want to use the new AutofacWebApiDependencyResolver class.

But if I do this with AutofacWebApiDependencyResolver i got this error:

The type Autofac.Integration.WebApi.AutofacWebApiDependencyResolver does not appear to implement Microsoft.Practices.ServiceLocation.IServiceLocator.

I read that i have to do this now for setting the resolver:

GlobalConfiguration.Configuration.DependencyResolver = new AutofacWebApiDependencyResolver(container);

But if I set it with '=', it is not set. Its still the DefaultResolver...

If I use the MVC AutofacDependencyResolver class again, it works.

Are were still problems with autofac and web api rtm? (the current integration is RC version)

回答1:

ASP.Net Wep.API and ASP.NET MVC uses two different IDependencyResolver (because they designed the Wep.API to not depend on ASP.NET MVC) so you need to setup both:

var container = builder.Build();
DependencyResolver.SetResolver(new AutofacDependencyResolver(container));
GlobalConfiguration.Configuration.DependencyResolver = 
     new AutofacWebApiDependencyResolver(container);

So the AutofacDependencyResolver is needed to inject decencies to regular MVC Controller derived controllers.

And the AutofacWebApiDependencyResolver is needed to inject dependencies to the Web.API ApiController derived controllers.

And don't forget to register your Api controllers in your container builder with the call (it differs from usual builder.RegisterControllers method):

builder.RegisterApiControllers(Assembly.GetExecutingAssembly());

回答2:

Following is a very good example

Using Autofac with Web Api