Define the components appropriately for the application and create project for each one.
3 Things: Visual Things, Business Things (Domain Entities), Application Things (like Logging & Email Generation)
3 Types: User interface classes, Domain entity classes, Library class
Class is a template or mold,specifies the traits or data,specifies the behavior or operations.
原文:http://www.cnblogs.com/lmfy/p/5103328.html