上传时候并没有报错而且看文件大小也对

    private bool Upload(string fileName)
    {
        FtpWebRequest ftpWebRequest = null;
        FileStream locaFileStream = null;
        Stream requestStream = null;
        try
        {
            //读取文件
            FileInfo fileInfo = new FileInfo(fileName);

            //连接FTP资源
            ftpWebRequest = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpIp + "/" + fileInfo.Name));
            //登录用户名和密码
            ftpWebRequest.Credentials = new NetworkCredential(user, pwd);
            //默认为true，连接不会关闭
            ftpWebRequest.KeepAlive = false;
            //执行什么命令
            ftpWebRequest.Method = WebRequestMethods.Ftp.UploadFile;
            //文件大小
            ftpWebRequest.ContentLength = fileInfo.Length;
            //传输类型
            ftpWebRequest.UseBinary = true;

　　　　//这里本来是缓存大小啊。但是我改变成和文件大小一样上传就成功,我改成2048上传文件只有2KB 很不解啊我查了N多资料都说这个属性是每次读取晓得啊求解释啊

            int byteLength = (int)fileInfo.Length;
            byte[] buff = new byte[byteLength];
            int contntLen = 0;
            //读取给定路径文件
            locaFileStream = fileInfo.OpenRead();
            //得到流
            requestStream = ftpWebRequest.GetRequestStream();
            //每次读取流
            contntLen = locaFileStream.Read(buff, 0, byteLength);
            if (contntLen != 0)
            {
                requestStream.Write(buff, 0, byteLength);
                contntLen = locaFileStream.Read(buff, 0, contntLen);
                return true;
            }
            return false;
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
            return false;
        }
        finally
        {
            if (requestStream != null)
            {
                requestStream.Close();
            }
            if (locaFileStream != null)
            {
                locaFileStream.Close();
            }
        }
    }