The C# Programming Language, Third Edition

13. Interfaces

An interface defines a contract. A class or struct that implements an interface must adhere to its contract. An interface may inherit from multiple base interfaces, and a class or struct may implement multiple interfaces.

BILL WAGNER   Interfaces work best when they are small in scope and few in number. Larger interfaces create more work for implementers. Larger numbers of interfaces provide more opportunities for ambiguity and collisions.

Interfaces can contain methods, properties, events, and indexers. The interface itself does not provide implementations for the members that it defines. Instead, it merely specifies the members ...