Question

I have an MVC3 app using Autofac and a custom membership provider.

If I try and inject the provider using the ctor, I get an error: ‘No parameterless constructor defined for this object.’

public class MyMemberShipProvider : MembershipProvider
    {

        IUserRepository userRepository;

  public MyMemberShipProvider(IUserRepository userRepository)
        {
            this.userRepository = userRepository;

        }

Answer 1

You can not inject into the in-built providers (Membership / Roles).
You can use the MVC 3 DependencyResolver with Autofac.

A quick example…

public override bool ValidateUser(string username, string password)
{
    var userRepo = DependencyResolver.Current.GetService<IUserRepository>();
    return userRepo.ValidateUser(username, password);
}