c#遍历一个文件夹下的所有文件包括子文件夹【原】

/// <summary>
        /// 遍历目录所有文件
        /// </summary>
        /// <param name="directory">目录</param>
        /// <param name="searchPattern">要查找的文件（*.txt）</param>
        /// <returns></returns>
        public static FileInfo[] GetFileList(DirectoryInfo directory, string searchPattern)
        {
            FileInfo[] fis = new FileInfo[0];
            DirectoryInfo[] directorys = directory.GetDirectories();
            foreach (DirectoryInfo di in directorys)
            {
                FileInfo[] fiss = GetFileList(di,searchPattern);
                AddNewArray<FileInfo>(ref fis, fiss);
            }
            AddNewArray<FileInfo>(ref fis, directory.GetFiles(searchPattern));
            return fis;
        }

        /// <summary>
        /// 遍历目录所有文件大小
        /// </summary>
        /// <param name="directory">目录</param>
        /// <param name="searchPattern">要查找的文件（*.txt）</param>
        /// <param name="symbol">是否带符号</param>
        /// <returns></returns>
        public static string GetFileListLength(DirectoryInfo directory, string searchPattern, bool symbol)
        {
            int fileListLength = 0;
            
            foreach (FileInfo fi in GetFileList(directory, searchPattern))
            {
                fileListLength += (int)fi.Length;
            }
            return getSizeType(fileListLength, symbol);
        }

        /// <summary>
        /// 合并数组
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="A"></param>
        /// <param name="B"></param>
        public static void AddNewArray<T>(ref T[] A, T[] B)//合并数组，运用了一个范型，具体作用见下文
        {
            T[] A1;
            A1 = (T[])A.Clone();
            A = new T[A1.GetLength(0) + B.GetLength(0)];
            for (int i = 0; i < A1.GetLength(0); i++)
            {
                A[i] = A1[i];
            }
            for (int i = 0; i < B.GetLength(0); i++)
            {
                A[i + A1.GetLength(0)] = B[i];
            }
        }


        /// <summary>
        /// 格式化大小符号
        /// </summary>
        /// <param name="fileSize"></param>
        /// <param name="symbol">是否带符号</param>
        /// <returns></returns>
        public static string getSizeType(int fileSize, bool symbol)
        {
            string fileInfo = "0B";
            if (fileSize > 0)
            {
                if (fileSize / 1024 > 0)
                {
                    if (fileSize / 1024 / 1024 > 0)
                    {
                        if (fileSize / 1024 / 1024 / 1024 > 0)
                        {
                            fileInfo = (fileSize / 1024.0 / 1024.0 / 1024.0).ToString("0.0") + (symbol ? " GB" : "");
                        }
                        else
                        {
                            fileInfo = (fileSize / 1024.0 / 1024).ToString("0.0") + (symbol ? " MB" : "");
                        }
                    }
                    else
                    {
                        fileInfo = (fileSize / 1024.0).ToString("0.0") + (symbol ? " KB" : "");
                    }
                }
                else
                {
                    fileInfo = fileSize + (symbol ? " B" : "");
                }
            }
            return fileInfo;
        }