C#修改目录和文件权限

因为之前工作需要，需要修改IIS下某网站文件和文件的权限：

string path = info.WebSitePath;
                DirectoryInfo dirInfo = new DirectoryInfo(path);
                DirectorySecurity dirSec = dirInfo.GetAccessControl();
                IdentityReference user =
                    new NTAccount("IIS_IUSRS");

                FileSystemAccessRule accRule
                    = new FileSystemAccessRule(user,FileSystemRights.FullControl,
                         AccessControlType.Allow);

                dirSec.AddAccessRule(accRule);
                dirInfo.SetAccessControl(dirSec);

                string filePath = info.WebSitePath + @"\ServiceReferences.ClientConfig.xml";
                FileInfo fileInfo = new FileInfo(filePath);
                FileSecurity fileSec = fileInfo.GetAccessControl();
                fileSec.AddAccessRule(accRule);
                fileInfo.SetAccessControl(fileSec);