ps: http://waf.codeplex.com/releases/view/618696
This page might help you to understand what MEF does in the sample applications.帮助理解 MEF MEF(Managed Extensibility Framework)是一个用于创建可扩展的轻型应用程序的库。
n-tier waf 41 project 层真够多
原文：http://www.cnblogs.com/ganmk--jy/p/5539067.html
