Question

I know interfaces cannot define constructors. What is the best practice to force all classes implementing an interface, to receive their dependencies in a uniform contract. I know ints possible to inject dependencies into objects via properties, but passing them via constructors makes more sense to me. How to DI then ?

Answer 1

We all know this is possible by many different methods, but something that makes sense is more welcome surely. I defined some set-only properties, then the object is responsible to holding a reference to what is passed to it:

public interface IBlogRepository
{
    ISession Session { set; }
}

class BlogRepository : IBlogRepository
{
   private ISession m_session;

   ISession Session
   {
      set { m_session = value; }
   }
}

This way every class implementing the interface knows that the set-only property is a dependency injection, since set-only properties are rarely used. I’m not sure if this method is known as a good practice or not, but for me it is, from now.