Stream Read

看过很多回 关于 stream read(byte[] buffer, int offset, int count)

有个问题一直没注意过

offset + count 不能超过 buffer的长度

所以

FileStream stream = new FileStream(txtAttachments.Text, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
            byte[] bytes = new byte[stream.Length];

            int numRead = 0;
            int count = 50 > bytes.Length ? bytes.Length : 50;
            int numToRead = bytes.Length;
            int offset = 0;
            while (numToRead > 0)
            {
                numRead = stream.Read(bytes, offset, count);
                if (numRead == 0)
                    break;
                numToRead = numToRead - numRead;
                offset = offset + numRead;

                if (numToRead < count)
                    count = numToRead;
            }
            
            stream.Close();

有个问题没想明白,如果文件长度1000, 我请求900,难道它会只返回700?