uITestControl.Exists为我完成了窍门.

此方法将返回一个布尔值，该值对应于正在打开的应用程序窗口的存在.这样可以创建一个if语句，如果尚未打开该应用程序，则可以打开该应用程序；如果已经打开，则不执行任何操作.

This method will return a boolean value corresponding to the existence of the application window being open. This allows an if statement to be created that can open the application if not already open, or do nothing if its already open.