Dependency Injection

In my day job I've been helping architect a restful service framework for another group.  Amazingly the 'legacy' system developers in this group weren't aware of dependency injection.  After seeing their eye glaze over by trying to explain the concept I decided to hunt around for a simple example.  I was surprised at how bad most of the explanations and examples out there are.  Fortunately I stumbled across this excellent blog post on CodeArsenal.net.

http://www.codearsenal.net/2015/03/c-sharp-dependency-injection-simple.html#.Wo5cBq6WbmE

I showed it to the developers and they said it instantly clicked.