使用WPF实现的后台处理耗时任务时前台显示等待动画Demo，动画效果是仿Win8等待效果，用了第三方库，可以自己实现其他动画效果。-When implemented using WPF background processing to wait for time-consuming tasks front display animation Demo, animation Win8 wait imitation effect, with a third-party library, you ca