将带有已定义类型的通用接口注册到没有类型的通用接口有什么区别？

Question

I have a problem on how to register my generic interface implemented into multiple class in my UnityContainer and I figured it out using this code.

container.RegisterType(typeof (IRepository<Location>), typeof (LocationRepository));
container.RegisterType(typeof (IRepository<ProductDto>), typeof (ProductRepository));
container.RegisterType(typeof (IRepository<Customer>), typeof (CustomerRepository));
container.RegisterType(typeof (IRepository<CustomerAddress>), typeof (CustomerAddressRepository));
container.RegisterType(typeof (IRepository<CustomerTerms>), typeof (CustomerTermRepository));
container.RegisterType(typeof (IRepository<AmountDto>), typeof (ProductListPricingRepository));
container.RegisterType(typeof (IRepository<Contact>), typeof (ContactRepository));

Above code is working as expected but out of my curiosity I also tried to experiment a little bit and register it without a defined type like code below and it seems working same as the first one.

container.RegisterType(typeof (IRepository<>), typeof (LocationRepository));
container.RegisterType(typeof (IRepository<>), typeof (ProductRepository));
container.RegisterType(typeof (IRepository<>), typeof (CustomerRepository));
container.RegisterType(typeof (IRepository<>), typeof (CustomerAddressRepository));
container.RegisterType(typeof (IRepository<>), typeof (CustomerTermRepository));
container.RegisterType(typeof (IRepository<>), typeof (ProductListPricingRepository));
container.RegisterType(typeof (IRepository<>), typeof (ContactRepository));

Now my question are:

1. What is/are the difference between the two aside from readability of the code?

2. Is their any implication if I choose one of it?

3. What is the best practice if I have this code?

Answer 1

Second method named open generic registration. This method useful when your concrete classes also generic then you don't need to register a type for each classes.

For example if you have:

interface IRepository<T>{}

and

class Repository<T>:IRepository<T>{}

simply in IoC you could write one simple line:

container.RegisterType(typeof (IRepository<>), typeof (Repository<>));

instead of

container.RegisterType(typeof (IRepository<User>), typeof (Repository<User>));
container.RegisterType(typeof (IRepository<Product>), typeof (Repository<Product>));
container.RegisterType(typeof (IRepository<Customer>), typeof (Repository<Customer>));
container.RegisterType(typeof (IRepository<CustomerAddress>), typeof (Repository<CustomerAddress>));
// and so on

As you can see without open generic registration we need register separately for each item