WebClient

//WebClient wc = new WebClient();
            //wc.DownloadFile("http://192.168.1.100/b.xls", @"c:\b.xls");

            //using(Stream stream = File.OpenRead(@"c:\b.xls"))
            //{
            //    HSSFWorkbook workbook = new HSSFWorkbook(stream);
            //    HSSFSheet sheet = workbook.GetSheetAt(0);
            //    HSSFRow row = sheet.GetRow(0);
            //    MessageBox.Show(row.GetCell(0).StringCellValue);
            //}

            //WebClient wc = new WebClient();
            //Stream stream = wc.OpenRead("http://192.168.1.100/b.xls");

            ////有的Stream子类不支持指针的后退、Seek
            ////stream.Position = 2;
            //using (stream)
            //{
            //    //HSSFWorkbook要求一个指针能随意移动的流
            //    HSSFWorkbook workbook = new HSSFWorkbook(stream);
            //    HSSFSheet sheet = workbook.GetSheetAt(0);
            //    HSSFRow row = sheet.GetRow(0);
            //    MessageBox.Show(row.GetCell(0).StringCellValue);
            //}

            WebClient wc = new WebClient();
            Stream stream = wc.OpenRead("http://192.168.1.100/b.xls");
            //stream.po
            //存放数据到内存流中
            using (Stream memstream = new MemoryStream())
            {
                //因为所有数据都拷贝到了memstream，所以考完了就可以Dispose
                using (stream)
                {
                    //从stream读取到memstream中
                    byte[] bytes = new byte[1024];
                    int readBytes;
                    //把网络流中的数据读到bytes数组中
                    while ((readBytes = stream.Read(bytes, 0, bytes.Length)) > 0)
                    {
                        //把bytes数组中的数据写入到内存流中
                        memstream.Write(bytes, 0, readBytes);
                    }
                }
                HSSFWorkbook workbook = new HSSFWorkbook(memstream);
                HSSFSheet sheet = workbook.GetSheetAt(0);
                HSSFRow row = sheet.GetRow(0);
                MessageBox.Show(row.GetCell(0).StringCellValue);
            }
            
        }