C#中一个简单的递归（查看文件总个数）

        //总共多少个文件
        public int allfilenum(string filepath)
        {
            DirectoryInfo dir = new DirectoryInfo(filepath);
            FileInfo[] fis = dir.GetFiles();
            if (fis.Length > 0)
            {
                allnum++;
            }
            else
            {
                foreach (DirectoryInfo folder2 in dir.GetDirectories())
                {
                    allfilenum(folder2.FullName);
                }
            }
            return allnum;
        }