Extension Framework in AX2012

Introduction:

The basic idea of extension framework is that Frameworks, and their Foundation components  must adhere to the Open-Closed principle. This principle states that “software entities should be open to extension, but closed to modification”  this means that extending framework classes should not require changes to the any framework artifacts (classes, tables, Enums).

I found a great post on this..

http://dynamicsaxcloud.blogspot.co.uk/2012/12/ms-dynamics-ax-extension-framework.html

Enjoy ...