Question

我正在尝试通过拖放将多个文件添加到FTP服务器，我可以使用try catch块来执行此操作，如果我们正确地提供ftp设置，则上传它们需要1秒，但是当我们提供错误的详细信息时如果我发出特殊消息，我会挂断并且不会给我任何错误消息。

现在我收到错误消息以及我添加的每个文件的成功消息。我不希望这种情况发生。

任何人都可以说我应该在哪里提供成功和失败的消息，以便上传需要几秒钟，如果不能立即给我留言。

在我出错的地方，我感到很困惑。

任何帮助将不胜感激！

这是我的代码：

Private Sub uploadFile(ByVal FTPAddress As String, ByVal filePath As String, ByVal username As String, ByVal password As String) 'Create FTP request

    Try
        Dim request As FtpWebRequest = DirectCast(FtpWebRequest.Create(FTPAddress & "/" & Path.GetFileName(filePath)), FtpWebRequest)

        request.Method = WebRequestMethods.Ftp.UploadFile
        request.Credentials = New NetworkCredential(username, password)
        request.UsePassive = True
        request.UseBinary = True
        request.KeepAlive = False

        Dim buffer As Byte() = Nothing
        'Load the file
        Using stream As FileStream = File.OpenRead(filePath)
            buffer = New Byte(CInt(stream.Length - 1)) {}
            stream.Read(buffer, 0, buffer.Length)
        End Using

        'Upload file
        Using reqStream As Stream = request.GetRequestStream()
            reqStream.Write(buffer, 0, buffer.Length)
        End Using

        MsgBox("Uploaded Successfully", MsgBoxStyle.Information)
    Catch
       MsgBox("Failed to upload.Please check the ftp settings", MsgBoxStyle.Critical)
    End Try
End Sub

以下是拖放代码

 Private Sub FlowLayoutPanel1_DragDrop(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles FlowLayoutPanel1.DragDrop
    Try

        Dim Files As String() = CType(e.Data.GetData(DataFormats.FileDrop), String())

        For Each FileName As String In Files
                           Dim Extension As String = Path.GetExtension(FileName).ToLower
            If Array.IndexOf(SupportedExtensions, Extension) <> -1 Then
                uploadFile(txtFTPAddress.Text, FileName, txtUsername.Text, txtPassword.Text)

            End If

        Next
    Catch

    End Try

End Sub

Answer 1

由于每次加载文件时都会调用uploadFile，因此您可能希望将错误处理代码从此方法移动到dragDrop方法。这样，您将只收到一条消息，说明整个操作成功或失败。您还可以在FtpWebRequest上设置Timeout属性，以便在超过几秒钟时取消上传。

然后uploadFile变为：

Private Sub uploadFile(ByVal FTPAddress As String, ByVal filePath As String, ByVal username As String, ByVal password As String) 'Create FTP request
    Dim request as FtpWebRequest = ...
    request.Timeout = 5000 ' Set timeout to 5 seconds
    '... several lines omitted
    'Upload file
    Using reqStream As Stream = request.GetRequestStream()
        reqStream.Write(buffer, 0, buffer.Length)
    End Using
End Sub

然后，您可以将错误处理代码移动到处理拖放的方法中：

Private Sub FlowLayoutPanel1_DragDrop(ByVal sender As Object, ByVal e As  
    System.Windows.Forms.DragEventArgs) Handles FlowLayoutPanel1.DragDrop
    Try
       ' ... several lines omitted
       Next
       MsgBox("Uploaded Successfully", MsgBoxStyle.Information)
    Catch
       MsgBox("Failed to upload.Please check the ftp settings", MsgBoxStyle.Critical)
    End Try
End Sub

使用VB.net通过拖放到FTP服务器上传多个文件时出现问题

1 个答案: