统一使用相同的接口，多个工厂

所以，问题是，当我宣布：

So the issue, is when I declare:

[Dependency]
public AuthenticationService _authenticationServices { get; set; }

的 _authenticationServices 将不断保持空。它不被引用，这将抛出一个空引用异常。我假设的问题，从我的统一配置文件茎：

The _authenticationServices will constantly remain null. It isn't referenced, which will throw a Null Reference Exception. I'm assuming the issue stems from my Unity Configuration file:

container.RegisterType<ICrudFactory, ZNodeDataContextFactory>();
container.RegisterType<ICrudFactory, MincronDataContextFactory>();

因为它们都使用相同的接口，而是一个独立的具体实施。实现如下：

Since they both use the same interface, but a separate concrete implementation. The implementation is as follows:

public interface ICrud : IDisposable
{
     // Method's to be exposed, via general repository.
}

public interface ICrudFactory
{
     ICrud Create();
}

public ZNodeDataContext : DbContext, ICrud
{
     // Concrete implementation.
}

public MincronDataContext : DbContext, ICrud
{
     // Concrete implementation.
}

public ZNodeDataContextFactory : ICrudFactory
{
     ICrud ICrudFactory.Create()
     {
           return ZNodeDataContext();
     }
}

public MincronDataContextFactory : ICrudFactory
{
     ICrud ICrudFactory.Create()
     {
           return MincronDataContext();
     }
}

public class AuthenticationService
{
     private readonly ICrudFactory _factory;
     public AuthenticationService(ICrudFactory factory)
     {
         _factory = factory;
     }

     public void Sample()
     {
          using(var context = _factory.Create())
              context.Method(...);
     }
}

我想保持这种结构，避免code重复。

I'd like to keep that structure, to avoid code duplication.