c# - FtpWebRequest 错误

Question

我正在运行以下内容：

            try
        {
            var ftpWebRequest = (FtpWebRequest)WebRequest.Create("ftp://webftp.ftp.com");
            ftpWebRequest.Credentials = new NetworkCredential("user", "password");
            ftpWebRequest.Method = WebRequestMethods.Ftp.UploadFile;
            using (var inputStream = File.OpenRead(@data))
            using (var outputStream = ftpWebRequest.GetRequestStream())
            {
                var buffer = new byte[1024 * 1024];
                int totalReadBytesCount = 0;
                int readBytesCount;
                while ((readBytesCount = inputStream.Read(buffer, 0, buffer.Length)) > 0)
                {
                    outputStream.Write(buffer, 0, readBytesCount);
                    totalReadBytesCount += readBytesCount;
                    var progress = totalReadBytesCount * 100.0 / inputStream.Length;
                    uploader.ReportProgress((int)progress);
                }
            }
        }
        catch (Exception es)
        {
            MessageBox.Show(es.ToString());
        }

@data 是文件的完整本地路径。

我每次收到的错误如下：

System.Net.WebException：请求的 URI 对于此 FTP 命令无效。在 System.Net.FtpWebRequest.GetRequestStream()

我已经通过 cmd 尝试了 ftp 连接，它工作得非常好。