同时创建两个进程，实现两个窗口的显示，其中一个作为主窗口控制另一个的开启和关闭，同时添加对其的消息控制；据此可以实现后台程序的建立；已经使用与扩展屏幕显示程序。-also create two processes, to achieve the two windows, one of the main window as another control the opening and closing, the news added to its control; Accordingly back