类似CAD绘图的代码，绘图、拖动、分层选择物件等功能

用VB编写的完整的CAD程序，源代码提供，可以借鉴开发自己的CAD版本，一点遗憾的是说明是法语,VB prepared with a complete CAD program, source code provided, you can learn to develop their own version of the CAD, A LITTLE regret is that it is French