Key class that consists of a primary and secondary component. Two instances of CompositeKey are considered to be equal iff both the primary and secondary components of the two instances are considered equal. Additionally, the hash code of a CompositeKey takes into the consideration the hash codes of its two components. Finally, the CompositeKey class implements KeyAssociation by returning the primary component.

public class CompositeKey : IPortableObject, 
	IKeyAssociation