c# - 如何解决 FTP 550 错误“访问被拒绝”，因为上传时连接不良

Question

如何解决 FTP 550 错误“访问被拒绝”，因为上传时连接不良。我确定我的服务器已经授予权限，因为有时我可以毫无问题地上传。我读过一些帖子说发生这种情况是因为服务器的连接速度很慢，但我想知道是否有人可以解决这个问题

这是我的代码：

public bool FTPUploadFunct(string uploadto2, string newskinlocation2)
    {
        bool FTPUploadFunct = true;
        MethodInvoker methodInvokerDelegate = delegate()
        { toolStripStatusLabel1.Text = "Uploading...."; };
        this.Invoke(methodInvokerDelegate);
        try
        {
            //delete old file
            FtpWebRequest requestFileDelete = (FtpWebRequest)WebRequest.Create(uploadto2);
            requestFileDelete.Credentials = new NetworkCredential("FTPUser20", "1234");
            requestFileDelete.Method = WebRequestMethods.Ftp.DeleteFile;

            FtpWebResponse responseFileDelete = (FtpWebResponse)requestFileDelete.GetResponse();

            //upload new file
            FtpWebRequest requestFTPUploader = (FtpWebRequest)WebRequest.Create(uploadto2);
            requestFTPUploader.Credentials = new NetworkCredential("FTPUser20", "1234");
            requestFTPUploader.Method = WebRequestMethods.Ftp.UploadFile;

            FileInfo fileInfo = new FileInfo(newskinlocation2);
            FileStream fileStream = fileInfo.OpenRead();

            int bufferLength = 2048;
            byte[] buffer = new byte[bufferLength];

            Stream uploadStream = requestFTPUploader.GetRequestStream();
            int contentLength = fileStream.Read(buffer, 0, bufferLength);

            while (contentLength != 0)
            {
                backgroundWorker1.ReportProgress((int)(contentLength / fileInfo.Length));
                uploadStream.Write(buffer, 0, contentLength);
                contentLength = fileStream.Read(buffer, 0, bufferLength);
            }

            uploadStream.Close();
            fileStream.Close();
            backgroundWorker1.ReportProgress(100);

            requestFTPUploader = null;
        }
        catch (WebException ex)
        {
            FTPUploadFunct = false;
            String status = ((FtpWebResponse)ex.Response).StatusDescription;
            MessageBox.Show(status + "error while in FTPUploadFunc");
            errorNumber = (int)((FtpWebResponse)ex.Response).StatusCode;
            if (errorNumber == 550)
            {
                MessageBox.Show("550" + "error while in FTPUploadFunc2");
            };
        }
        return FTPUploadFunct;
    } 

很多时候它卡在

requestFileDelete.Method = WebRequestMethods.Ftp.DeleteFile;

但有时在

requestFTPUploader.Method = WebRequestMethods.Ftp.UploadFile;

Answer 1

最后我找到了90%的成功率。并等待上传新文件约 3.5 秒

Cursor = Cursors.WaitCursor;
System.Threading.Thread.Sleep(3500);
Cursor = Cursors.Default;