相信大家都已经见过了，就是一个载入动画，环形的圆环在不停的旋转，支持FireFox、IE7、Mac等多种风格，还可以背景透明，这是C#专用控件。-I believe we all have seen, is a load animation, the annular ring spinning, support FireFox, IE7, Mac and a variety of styles, but also a transparent background, which is the ex