环境变量是包含诸如驱动器、路径或文件名之类的字符串。本程序创建了一个对话框，用户可以根据需要从对话框的按钮选项中选择服务，服务包括查询、设置和修改系统环境变量。-environment variables are included, such as actuators, path or file name like strings. The procedure created a dialog, users may need from the dialog button option to ch