Using Interface variables

Question

I\'m still trying to get a better understanding of Interfaces. I know about what they are and how to implement them in classes.

What I don\'t understand is when you

Answer 1

This is a fundamental concept in object-oriented programming -- polymorphism. (wikipedia)

The short answer is that by using the interface in Class A, you can give Class A any implementation of IMyInterface.

This is also a form of loose coupling (wikipedia) -- where you have many classes, but they do not rely explicitly on one another -- only on an abstract notion of the set of properties and methods that they provide (the interface).