跪求VB.NET 连接FTP

Question

跪求VB.NET 连接FTP 怎么都不行 即将崩溃 用INET 和 API的InternetOpen

InternetOpen 总是返回空 就是 失败

请问谁有方法 在线等

或者 只要能连接FTP 测试账号密码正确与否就成

Answer 1

Imports System.Net
Imports System.IO

Module FtpSample

Sub Main(ByVal args() As String)
If args.Length = 0 OrElse args(0).Equals("/?") Then
DisplayUsage()
ElseIf args.Length = 1 Then
Download(args(0))
ElseIf args.Length = 2 Then
If args(0).Equals("/list") Then
List(args(1))
Else
Upload(args(0), args(1))
End If
Else
Console.WriteLine("Unrecognized argument.")
End If
End Sub

Private Sub DisplayUsage()
Console.WriteLine("USAGE:")
Console.WriteLine(" FtpSample [/? | <FTP download URL> | <local file>")
Console.WriteLine(" <FTP upload URL> | /list <FTP list URL>]")
Console.WriteLine()
Console.WriteLine("where")
Console.WriteLine(" FTP download URL URL of a file to download from an FTP server.")
Console.WriteLine(" FTP upload URL Location on a FTP server to upload a file to.")
Console.WriteLine(" FTP list URL Location on a FTP server to list the contents of.")
Console.WriteLine(" local file A local file to upload to an FTP server.")
Console.WriteLine()
Console.WriteLine(" Options:")
Console.WriteLine(" /? Display this help message.")
Console.WriteLine(" /list Specifies the list command.")
Console.WriteLine()
Console.WriteLine("EXAMPLES:")
Console.WriteLine(" Download a file FtpSample ftp://myserver/download.txt")
Console.WriteLine(" Upload a file FtpSample upload.txt ftp://myserver/upload.txt")
End Sub

Private Sub Download(ByVal downloadUrl As String)
Dim responseStream As Stream = Nothing
Dim fileStream As FileStream = Nothing
Dim reader As StreamReader = Nothing
Try
Dim downloadRequest As FtpWebRequest = _
WebRequest.Create(downloadUrl)
Dim downloadResponse As FtpWebResponse = _
downloadRequest.GetResponse()
responseStream = downloadResponse.GetResponseStream()

Dim fileName As String = _
Path.GetFileName(downloadRequest.RequestUri.AbsolutePath)

If fileName.Length = 0 Then
reader = New StreamReader(responseStream)
Console.WriteLine(reader.ReadToEnd())
Else
fileStream = File.Create(fileName)
Dim buffer(1024) As Byte
Dim bytesRead As Integer
While True
bytesRead = responseStream.Read(buffer, 0, buffer.Length)
If bytesRead = 0 Then
Exit While
End If
fileStream.Write(buffer, 0, bytesRead)
End While
End If
Console.WriteLine("Download complete.")
Catch ex As UriFormatException
Console.WriteLine(ex.Message)
Catch ex As WebException
Console.WriteLine(ex.Message)
Catch ex As IOException
Console.WriteLine(ex.Message)
Finally
If reader IsNot Nothing Then
reader.Close()
ElseIf responseStream IsNot Nothing Then
responseStream.Close()
End If
If fileStream IsNot Nothing Then
fileStream.Close()
End If
End Try
End Sub

Private Sub Upload(ByVal fileName As String, ByVal uploadUrl As String)
Dim requestStream As Stream = Nothing
Dim fileStream As FileStream = Nothing
Dim uploadResponse As FtpWebResponse = Nothing
Try
Dim uploadRequest As FtpWebRequest = WebRequest.Create(uploadUrl)
uploadRequest.Method = WebRequestMethods.Ftp.UploadFile

' UploadFile is not supported through an Http proxy
' so we disable the proxy for this request.
uploadRequest.Proxy = Nothing

requestStream = uploadRequest.GetRequestStream()
fileStream = File.Open(fileName, FileMode.Open)

Dim buffer(1024) As Byte
Dim bytesRead As Integer
While True
bytesRead = fileStream.Read(buffer, 0, buffer.Length)
If bytesRead = 0 Then
Exit While
End If
requestStream.Write(buffer, 0, bytesRead)
End While

' The request stream must be closed before getting the response.
requestStream.Close()

uploadResponse = uploadRequest.GetResponse()
Console.WriteLine("Upload complete.")
Catch ex As UriFormatException
Console.WriteLine(ex.Message)
Catch ex As IOException
Console.WriteLine(ex.Message)
Catch ex As WebException
Console.WriteLine(ex.Message)
Finally
If uploadResponse IsNot Nothing Then
uploadResponse.Close()
End If
If fileStream IsNot Nothing Then
fileStream.Close()
End If
If requestStream IsNot Nothing Then
requestStream.Close()
End If
End Try
End Sub

Private Sub List(ByVal listUrl As String)
Dim reader As StreamReader = Nothing
Try
Dim listRequest As FtpWebRequest = WebRequest.Create(listUrl)
listRequest.Method = WebRequestMethods.Ftp.ListDirectoryDetails
Dim listResponse As FtpWebResponse = listRequest.GetResponse()
reader = New StreamReader(listResponse.GetResponseStream())
Console.WriteLine(reader.ReadToEnd())
Console.WriteLine("List complete.")
Catch ex As UriFormatException
Console.WriteLine(ex.Message)
Catch ex As WebException
Console.WriteLine(ex.Message)
Finally
If reader IsNot Nothing Then
reader.Close()
End If
End Try
End Sub

End Module

可以通过设置 Credentials 属性来指定用于连接服务器的凭据，也可以将它们包含在传递给 Create 方法的 URI 的 UserInfo 部分中。

从 FTP 服务器下载文件时，如果命令成功，所请求的文件的内容即在响应对象的流中。通过调用 GetResponseStream 方法，可以访问此流。

如果使用 FtpWebRequest 对象向服务器上载文件，则必须将文件内容写入请求流，请求流是通过调用 GetRequestStream 方法或其异步对应方法（BeginGetRequestStream 和 EndGetRequestStream 方法）获取的。必须写入流并在发送请求之前关闭该流。

请求是通过调用 GetResponse 方法或其异步对应方法（BeginGetResponse 和 EndGetResponse 方法）发送到服务器的。请求的操作完成时，会返回一个 FtpWebResponse 对象。FtpWebResponse 对象提供操作的状态以及从服务器下载的所有数据。

参考资料：msdn

Answer 2

先用 My.Computer.Network.Ping(IP_Addr)看IP地址通不通，再用My.Computer.Network.DownloadFile(URLPath, SavePath, UserName, PassWord)

我有个FTP定时取文件就用的这个，很好用噢。
URLPath="FTP://" & IP & "/" & FileName

---------------------------
使用.net后，尽量少用API,知道.NET为什么叫.NET么？就是网络功能很多都有现成的封装好的啦。^_^