C#读取写入流

            //读取
            FileStream rfs = new FileStream(@"x:\xxx\xxx.xxx", FileMode.Open, FileAccess.Read);
            //写入
            FileStream wfs = new FileStream(@"x:\xxx\xxx.xxx", FileMode.Create, FileAccess.Write);
            //每次传输大小
            int length = 1024 * 1024 * 5;
            byte[] buffer = new byte[length];
            //记录当前进度
            float _num = 0;
            int count = -1;
            while ((count = rfs.Read(buffer, 0, length)) != 0)
            {
                _num += buffer.Length;
                _num = Math.Clamp(_num, 0, rfs.Length);
                Console.WriteLine((_num * 100 / rfs.Length) + "%");
                wfs.Write(buffer, 0, count);
                wfs.Flush();
            }
            wfs.Close();
            rfs.Close();