Question

我几天来一直在努力。我正在尝试为某人创建功能，只需使用FileUpload Control将图像文件从本地计算机上传到FTP服务器。问题是，FileUpload控件无法显式检索要从客户端计算机上传的图像的路径，因此如果要从网络上的任何PC上传，我无法动态获取图像的源路径。 “SORT OF”的唯一方法是获取路径，或者说流是使用FileUpload.PostedFile.inputStream。然而，问题是将图像转换为字节数组。到目前为止我搜索过的功能都已经将文件上传到服务器，其中包含0个字节。如果我使用StreamReader（FileUpload.PostedFile.InputStream）并通过UTF8编码获取字节，则上传的图像具有字节但大于原始文件且图像已损坏。

以下是我用来上传的代码

Public Sub Upload()
    'FTP Server URL.
    Dim ftp As String = "ftp://winhost1.axxesslocal.co.za"

    'FTP Folder name. Leave blank if you want to upload to root folder.
    Dim ftpFolder As String = "/httpdocs/images/"

    Dim fileBytes As Byte() = Nothing

    'Read the FileName and convert it to Byte array.
    Dim fileName As String = Path.GetFileName(ImageUpload.FileName)
    Using fileStream As New StreamReader(ImageUpload.PostedFile.InputStream)

        fileBytes = Encoding.UTF8.GetBytes(fileStream.ReadToEnd())
        fileStream.Close()
    End Using

    'Create FTP Request.
    Dim request As FtpWebRequest = DirectCast(WebRequest.Create(ftp & ftpFolder & fileName), FtpWebRequest)
        request.Method = WebRequestMethods.Ftp.UploadFile

        'Enter FTP Server credentials.
        request.Credentials = New NetworkCredential("******", "******")
        request.ContentLength = fileBytes.Length
        request.UsePassive = True
        request.UseBinary = True
        request.ServicePoint.ConnectionLimit = fileBytes.Length
        request.EnableSsl = False

    Using requestStream As Stream = request.GetRequestStream()
            requestStream.Write(fileBytes, 0, fileBytes.Length)
            requestStream.Close()
        End Using

        Dim response As FtpWebResponse = DirectCast(request.GetResponse(), FtpWebResponse)


        response.Close()

End Sub

我知道问题在这里fileBytes = Encoding.UTF8.GetBytes（fileStream.ReadToEnd（））

但是我不知道如何将ImageUpload.PostedFile.InputStream（）转换为将给我一个未失真图像的字节。

Answer 1

您不需要进行任何UTF编码或解码，也不需要StreamReader。抓住字节。

fileStream = ImageUpload.PostedFile.InputStream
Dim fileBytes(0 to fileStream.Length - 1) as Byte
fileStream.Read(fileBytes, 0, fileBytes.Length)
fileStream.Close()

或者，如果您希望将缓冲区作为返回值，则可以使用BinaryReader：

Using binaryReader As New BinaryReader(ImageUpload.PostedFile.InputStream)
    fileBytes = binaryReader.ReadBytes(binaryReader.BaseStream.Length)
    binaryReader.Close()
End Using

如何将Stream转换为Byte（）

1 个答案: