文件分割和合并

        /// <summary>
        /// 文件分割方法
        /// </summary>
        /// <param name="sourceFile">要分割的文件</param>
        /// <param name="desDir">目标目录</param>
        /// <param name="TempExtra">分割后的小文件名</param>
        public void SplitFile(string sourceFile,string desDir, string[] TempExtra)
        {
            int iFileSize = 9 * 1024;
            if (Directory.Exists(desDir))
                Directory.Delete(desDir, true);
            else
                Directory.CreateDirectory(desDir);
            FileStream SplitFileStream = new FileStream(sourceFile, FileMode.Open);
            BinaryReader SplitFileReader = new BinaryReader(SplitFileStream);
            byte[] TempBytes;
            int iFileCount = (int)(SplitFileStream.Length / iFileSize);
            if (SplitFileStream.Length % iFileSize != 0) iFileCount++;
            for (int i = 1; i <= iFileCount; i++)
            {
                string sTempFileName = desDir + @"" + i.ToString().PadLeft(4, '0') + "." + TempExtra[TempExtra.Length - 1];
                
                FileStream TempStream = new FileStream(sTempFileName, FileMode.OpenOrCreate);
                BinaryWriter TempWriter = new BinaryWriter(TempStream);
                TempBytes = SplitFileReader.ReadBytes(iFileSize);
                TempWriter.Write(TempBytes);
                TempWriter.Close();
                TempStream.Close();
            }
            SplitFileReader.Close();
            SplitFileStream.Close();
        }

         /// <summary>
        /// 文件合并
        /// </summary>
        /// <param name="sDirectoryName">要合并为一个文件的目录</param>
        /// <param name="desFile">要合并成的目标文件</param>
        public void MergeFile(string sDirectoryName, string desFile)
        {
            string[] arrFileNames = Directory.GetFiles(sDirectoryName);
            int iSumFile = arrFileNames.Length;
            FileStream AddStream = new FileStream(desFile, FileMode.OpenOrCreate);
            BinaryWriter AddWriter = new BinaryWriter(AddStream);
            for (int i = 0; i < iSumFile; i++)
            {
                FileStream TempStream = new FileStream(arrFileNames[i], FileMode.Open);
                BinaryReader TempReader = new BinaryReader(TempStream);
                AddWriter.Write(TempReader.ReadBytes((int)TempStream.Length));
                TempReader.Close();
                TempStream.Close();
            }
            AddWriter.Close();
            AddStream.Close();
        }