Question

我发现此代码可以从FTP中的目录和子目录下载图像文件：
C# Download all files and subdirectories through FTP

所以这是我在VB.NET中的代码：

Private Sub DownloadFtpDirectory(ByVal url As String, ByVal credentials As NetworkCredential, ByVal localPath As String)
    Dim listRequest As FtpWebRequest = CType(WebRequest.Create(url), FtpWebRequest)
    listRequest.Method = WebRequestMethods.Ftp.ListDirectoryDetails
    listRequest.Credentials = credentials
    Dim lines As List(Of String) = New List(Of String)
    Dim listResponse As FtpWebResponse = CType(listRequest.GetResponse, FtpWebResponse)
    Dim listStream As Stream = listResponse.GetResponseStream
    Dim listReader As StreamReader = New StreamReader(listStream)

    While Not listReader.EndOfStream
        lines.Add(listReader.ReadLine)

    End While

    For Each line As String In lines
        Dim tokens As String() = line.Split({" "}, 9, StringSplitOptions.RemoveEmptyEntries)
        Dim name As String = tokens(8)
        Dim permissions As String = tokens(0)
        Dim localFilePath As String = Path.Combine(localPath, name)
        Dim fileUrl As String = (url + name)
        If (permissions(0) = ChrW(100)) Then
            If Not Directory.Exists(localFilePath) Then
                Directory.CreateDirectory(localFilePath)
            End If

            DownloadFtpDirectory((fileUrl + "/"), credentials, localFilePath)
        Else
            Dim downloadRequest As FtpWebRequest = CType(WebRequest.Create(fileUrl), FtpWebRequest)
            downloadRequest.Credentials = credentials
            downloadRequest.KeepAlive = False
            downloadRequest.Method = WebRequestMethods.Ftp.DownloadFile
            downloadRequest.UseBinary = True
            downloadRequest.Proxy = Nothing
            downloadRequest.UsePassive = False

            Dim downloadResponse As FtpWebResponse = CType(downloadRequest.GetResponse, FtpWebResponse)
            Dim sourceStream As Stream = downloadResponse.GetResponseStream
            Dim targetStream As FileStream = New FileStream(localFilePath, FileMode.Create)

            Dim buffer() As Byte = New Byte((10240) - 1) {}
            Dim read As Integer

            While (sourceStream.Read(buffer, 0, buffer.Length) > 0)
                targetStream.Write(buffer, 0, read)

            End While

        End If

    Next
End Sub

我用这个方法调用函数：

Private Sub btnDownloadImagesFromFTP_Click(sender As Object, e As EventArgs) Handles btnDownloadImagesFromFTP.Click
    Try             
        Dim credentials As NetworkCredential = New NetworkCredential("user", "password")
        Dim url As String = "ftp://myftp/imagesDirectory/"
        DownloadFtpDirectory(url, credentials, "C:\Users\Admin\Desktop\imagesFromFTP")
    Catch ex As Exception
        MessageBox.Show(ex.Message.ToString)
    End Try
End Sub

代码正常运行并下载带有图像文件和名称的子目录，但是当我打开任何图像时，它是空的（0字节）

任何人都知道为什么会这样？感谢。

Answer 1

您永远不会分配read变量。

While ((read = sourceStream.Read(buffer, 0, buffer.Length)) > 0)

图像文件从FTP下载0字节

1 个答案: