轻量级的CAD程序，很多思想是值得我们学习的。使用了接口技术，全面面向对象，有志涉足这个领域的朋友可以-lightweight CAD programs, many ideas are worthy of our study. The use of interface technology, comprehensive object-oriented, interested involvement in this area you can s

WPF 鼠标拖拽功能，自定义拖拽的跟随图形，不再是一个虚线的系统的小标志，而是具体所拖拽的对象的图形，比如拖一个button，后面跟随的就是一个button的形状。-WPF mouse drag and drop, drag the following custom graphics, broken system is no longer a small sign, but concrete by dragging a graphical object, such as dragging a b