Visual Basic FtpWebRequest下载文件？ [英] Visual Basic FtpWebRequest downloading files?

问题描述

我有：

  Dim ftploader As System.Net.FtpWebRequest = 
 DirectCast（System.Net。 WebRequest.Create（
ftp://ftp.cabbageee.host-ed.me/nim/Vardelatestmessage.txt），
 System.Net.FtpWebRequest）
 
 ftploader .Credentials = 
 New System.Net.NetworkCredential（在此处插入用户名，在此处插入密码）
  

我试图将 .txt 文件下载到我的 c：驱动器。我已经有一个连接，那么如何保存 .txt 文件？另外，我怎样才能上传文件？我已经尝试了 My.Computer.Network.DownloadFile ，但只能下载/上传一次，因为我不知道如何摆脱这种连接。 / p>

解决方案

使用VB.NET从FTP服务器下载二进制文件的最简单方法是使用 WebClient.DownloadFile ：

$ b $ pre $ Dim client As WebClient = New WebClient（）
client.Credentials = New NetworkCredential（username， password）
client.DownloadFile（
ftp://ftp.example.com/remote/path/file.zip，C：\local\path\file.zip ）

如果您需要更好的控制，那 WebClient 不提供，请使用 的FtpWebRequest 。简单的方法是使用 FileStream .stream.copyto.aspxrel =nofollow noreferrer> Stream.CopyTo ：

  Dim request As FtpWebRequest = 
 WebRequest.Create（ftp://ftp.example.com/remote/path/file.zip）
 request.Credentials = New NetworkCredential（username，password）
 request.Method = WebRequestMethods.Ftp.DownloadFile 
 
使用ftpStream As Stream = request.GetResponse（）。GetResponseStream（），
 fileStream As Stream = File.Create（C：\local\path\file.zip）
 ftpStream.CopyTo（fileStream）
结束使用
  
 
 
 
 
 
 
  Dim request As FtpWebRequest = 
 WebRequest.Create（ftp://ftp.example.com/remote/path/file.zip）
 request.Credentials =新建NetworkC （），
使用ftpStream As Stream = request.GetResponse（）。GetResponseStream（），
 fileStream As Stream = File.Create（C：\local\path\file.zip）
 Dim buffer As Byte（）= New Byte（10240  -  1）{} 
 Dim read As Integer 
 Do 
 read = ftpStream.Read（buffer，0，buffer.Length）
如果读取> 0然后
 fileStream.Write（buffer，0，read）
 Console.WriteLine（Downloaded {0} bytes，fileStream.Position）
 End If 
 Loop While read> ; 0 
结束使用
  
对于GUI进度（WinForms  ProgressBar ），请参阅（C＃）：
 
  FtpWebRequest FTP与ProgressBar下载  p> 
 
 
如果要从远程文件夹下载所有文件，请参阅
 
 如何使用VB.NET从FTP下载目录 
 
What I have:
Dim ftploader As System.Net.FtpWebRequest =
    DirectCast(System.Net.WebRequest.Create(
        "ftp://ftp.cabbageee.host-ed.me/nim/Vardelatestmessage.txt"),
        System.Net.FtpWebRequest)

ftploader.Credentials =
    New System.Net.NetworkCredential("Insert Username here", "Insert password here")
I am trying to download this .txt file to my c: drive. I already have a connection, so how can I save that .txt file? Also, how can I upload a file? I already tried My.Computer.Network.DownloadFile, but it is only possible to download/upload once, as I have no idea of how to get rid of that connection.
解决方案
The most trivial way to download a binary file from an FTP server using VB.NET is using WebClient.DownloadFile:
Dim client As WebClient = New WebClient()
client.Credentials = New NetworkCredential("username", "password")
client.DownloadFile(
    "ftp://ftp.example.com/remote/path/file.zip", "C:\local\path\file.zip")
If you need a greater control, that WebClient does not offer, use FtpWebRequest. Easy way is to just copy an FTP response stream to FileStream using Stream.CopyTo:
Dim request As FtpWebRequest =
    WebRequest.Create("ftp://ftp.example.com/remote/path/file.zip")
request.Credentials = New NetworkCredential("username", "password")
request.Method = WebRequestMethods.Ftp.DownloadFile

Using ftpStream As Stream = request.GetResponse().GetResponseStream(),
      fileStream As Stream = File.Create("C:\local\path\file.zip")
    ftpStream.CopyTo(fileStream)
End Using
If you need to monitor a download progress, you have to copy the contents by chunks yourself:
Dim request As FtpWebRequest =
    WebRequest.Create("ftp://ftp.example.com/remote/path/file.zip")
request.Credentials = New NetworkCredential("username", "password")
request.Method = WebRequestMethods.Ftp.DownloadFile

Using ftpStream As Stream = request.GetResponse().GetResponseStream(),
      fileStream As Stream = File.Create("C:\local\path\file.zip")
    Dim buffer As Byte() = New Byte(10240 - 1) {}
    Dim read As Integer
    Do
        read = ftpStream.Read(buffer, 0, buffer.Length)
        If read > 0 Then
            fileStream.Write(buffer, 0, read)
            Console.WriteLine("Downloaded {0} bytes", fileStream.Position)
        End If
    Loop While read > 0
End Using
For GUI progress (WinForms ProgressBar), see (C#):

FtpWebRequest FTP download with ProgressBar

If you want to download all files from a remote folder, see

How to download directories from FTP using VB.NET

                        
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