.net 获取和设置环境变量

        private void SetEnvironmentVariables()
        {
            string currPath = Application.StartupPath;
            //string pathVar = System.Environment.GetEnvironmentVariable("Path"); 需要指定EnvironmentVariableTarget,不然获得返回值不正确
            string pathVar = System.Environment.GetEnvironmentVariable("Path", EnvironmentVariableTarget.Machine);
            //如果不包含本程序的路径则写入path
            if (!(pathVar.ToUpper().Contains(currPath.ToUpper())))
            {
                System.Environment.SetEnvironmentVariable("PATH", pathVar + ";" + currPath, EnvironmentVariableTarget.Machine);
            }
        }