说明：  vs2008 + Catia V5 R21 CAA方式进行的二次开发文档，详细介绍了环境的搭建以及Catia下拉菜单的建立。
(vs2008+ Catia V5 R21 CAA approach to the secondary development of the document, detailing the build environment as well as the establishment of Catia drop-down menu.)