Asynchronous FTP Upload

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The Chilkat FTP component supports asynchronous uploads and downloads. This examples demonstrates doing an upload in a background thread. The upload is started by calling AsyncPutFileStart. While the upload is in progress, your program may do other tasks. You may periodically check the AsyncFinished property to determine when the transfer is finished. The example below provides the remainder of the details.

Dim ftp As New Chilkat.Ftp2()

Dim success As Boolean

' Any string unlocks the component for the 1st 30-days.
success = ftp.UnlockComponent("Anything for 30-day trial")
If (success <> true) Then
    MsgBox(ftp.LastErrorText)
    Exit Sub
End If


ftp.Hostname = "ftp.yourftpserver.com"
ftp.Username = "*myLogin6*"
ftp.Password = "*myPassword6*"


' Connect and login to the FTP server.
success = ftp.Connect()
If (success <> true) Then
    MsgBox(ftp.LastErrorText)
    Exit Sub
End If


' Change to the remote directory where the file will be uploaded.
success = ftp.ChangeRemoteDir("junk")
If (success <> true) Then
    MsgBox(ftp.LastErrorText)
    Exit Sub
End If


Dim localFilename As String
localFilename = "hamlet.xml"
Dim remoteFilename As String
remoteFilename = "hamlet.xml"

' Begin the upload in a background thread.
' Only 1 background upload or download may be active at any time.
' (per instance of an FTP object)
' To append to an existing file in the background, call
' AsyncAppendFileStart instead.
success = ftp.AsyncPutFileStart(localFilename,remoteFilename)
If (success <> true) Then
    MsgBox(ftp.LastErrorText)
    Exit Sub
End If


' The application is now free to do anything else
' while the file is uploading.
' For this example, we'll simply sleep and periodically
' check to see if the transfer if finished.  While checking
' however, we'll report on the progress in both number
' of bytes tranferred and performance in bytes/second.
While ftp.AsyncFinished <> true

    TextBox1.Text = TextBox1.Text & ftp.AsyncBytesSent _
         & " bytes sent" & vbCrLf
    TextBox1.Refresh()
    TextBox1.Text = TextBox1.Text & ftp.UploadRate _
         & " bytes per second" & vbCrLf
    TextBox1.Refresh()

    ' Sleep 1 second.
    ftp.SleepMs(1000)
End While

' Did the upload succeed?
If (ftp.AsyncSuccess = true) Then
    MsgBox("File Uploaded!")
Else
    ' The error information for asynchronous ops
    ' is in AsyncLog as opposed to LastErrorText
    MsgBox(ftp.AsyncLog)
End If


ftp.Disconnect()