如何使用Autofac注入asp.net mvc3自定义成员资格提供程序？

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);
}

Answer 2

Avoid resolving in application code (validate user, etc) as this is the service locator anti-pattern. You want to resolve only in your 'glue' code/low level code.

This below is for windsor, but the implementation can be easily adjusted. Here is one outlined for castle windsor, but the implementation should be similar. Its a bit cleaner as this resolves in the call to GetProvider - which is the 'glue' code here, thus avoiding the service locator anti-pattern usage in the actual membership functions (such as ValidateUser)

http://bugsquash.blogspot.com/2010/11/windsor-managed-membershipproviders.html

Answer 3

That´s because you should inject your userRepository as well. Something like:

protected override void Load(ContainerBuilder builder)
{
    builder.RegisterType<UserRepository>().As<IUserReposotory>();
    builder.RegisterType<MyMembershipProvider>();
}