Direct Uploading New Ftp listbox Lines

Question

Can i (Upload / Adding) Listbox Lines To Current Ftp listbox Lines Server Without download Previous ftp server Listbox value.

Instead of Uploading addition listbox lines To Ftp Listbox Lines Server !

Can I simply send listbox new lines and then it Added to currently listbox ftp server lines (without remove old lines, it only add new lines) With currently Ftp listbox Lines without me having to download and upload the whole ftp listbox?

Example : That's My Code

Download Code (Button 1) [not important]

   Dim request As FtpWebRequest =
   WebRequest.Create("ftp://test.com/test.txt")
   request.Method = WebRequestMethods.Ftp.DownloadFile
   request.Credentials = New NetworkCredential("tester1", 
           "password")

        Using response As FtpWebResponse = request.GetResponse(),
                  stream As Stream = response.GetResponseStream(),
                  reader As StreamReader = New StreamReader(stream)
            While Not reader.EndOfStream
                listbox1.Items.Add(reader.ReadLine())
            End While
        End Using

          ' Adding the listbox item's Before upload it again'

        listbox1.Items.Add(".")

Upload Code (Button 2)

[important to make it direct upload new lines to currently ftp listbox lines server]

                Dim request As FtpWebRequest =
                WebRequest.Create("ftp://test.com/test.txt")
                request.Method = WebRequestMethods.Ftp.UploadFile
                request.Credentials = New NetworkCredential("tester1", 
               "password")
                request.UseBinary = False

                Using stream As Stream = request.GetRequestStream(),
                          writer As StreamWriter = New StreamWriter(stream)
                    For index As Integer = 0 To listbox1.Items.Count - 1

                        writer.WriteLine(listbox1.Items(index))
                    Next
                End Using

            Catch ex As Exception

Regards

Answer 1

Note: I see you're using Visual Studio 2012. There's the chance that some of the code might not be supported (the .Net version is not specified). Comment about it if that's the case.

WebRequest supports the FTP APPE command for its FtpWebRequest incarnation.

See the WebRequestMethods.Ftp → WebRequestMethods.Ftp.AppendFile.

This method sends an Ftp APPE command. If the uploaded file exists, it will append the new content.
When writing a text file, you may want to append an Environment.Newline sequence to each line, if/when need.

Since you have a ListBox control, you can extract its Items text and prepend a line feed to each item string value this way:

Dim TextLines As String() = listBox1.Items.Cast(Of String)().Select(Function(ln) Environment.NewLine + ln).ToArray()

You can call the method that follows this way:

Dim result As Long = Await FtpAppenAsync("ftp://ftp.server.com/[EntryDir]/[ExistingFile]", TextLines)

Here's a modified method that allows to append some text lines to an existing text file on an FTP Server:
(Take note about the Encoding of the StreamWriter: it's set to Default → current Local Codepage.
When an Encoding is not specified, it defaults to UTF8. Modify as required).

Public Async Function FtpAppenAsync(ResourceName As String, TextData As String()) As Task(Of Integer)

    Dim request As FtpWebRequest = CType(WebRequest.Create(ResourceName), FtpWebRequest)
    request.Credentials = New NetworkCredential("[FtpAccount]", "[FtpPassword]")
    request.Method = WebRequestMethods.Ftp.AppendFile
    request.UseBinary = True
    request.UsePassive = True

    Dim TextLinesWritten As Integer = 0
    Try
        Using ftpStream As Stream = Await request.GetRequestStreamAsync()
            Using ftpWriter As New StreamWriter(ftpStream, Encoding.Default)
                For Each TextLine As String In TextData
                    Await ftpWriter.WriteAsync(TextLine)
                    TextLinesWritten += 1
                    Console.WriteLine("Uploaded {0} lines", TextLinesWritten)
                Next
            End Using
        End Using
        Using response As FtpWebResponse = CType(Await request.GetResponseAsync(), FtpWebResponse)
            'Log-Return the StatusCode of the failed upload
            If Not (response.StatusCode = FtpStatusCode.ClosingData) Then Return -1
        End Using
    Catch ex As Exception
        'Log/report ex
        TextLinesWritten = -1
        Throw
    End Try
    Return TextLinesWritten
End Function

If an Ssl connection is required, add the Imports and these lines: paste them on top of that method:
(The SecurityProtocolType depends on your connection requirements)

Imports System.Net.Security
Imports System.Security.Cryptography.X509Certificates

'Method code
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12

ServicePointManager.ServerCertificateValidationCallback =
    New RemoteCertificateValidationCallback(Function(s, Cert, Chain, sslErrors)
                                                Return True
                                            End Function)
request.EnableSsl = True