Yes, FTP protocol overwrites existing files on upload.
Note that there are better ways to implement the upload.
The most trivial way to upload a binary file to an FTP server using .NET framework is using WebClient.UploadFile:
Dim client As WebClient = New WebClient
client.Credentials = New NetworkCredential("username", "password")
client.UploadFile("ftp://ftp.example.com/remote/path/file.zip", "C:\local\path\file.zip")
If you need a greater control, that WebClient does not offer (like TLS/SSL encryption, ascii/text transfer mode, active mode, transfer resuming, etc), use FtpWebRequest. Easy way is to just copy a FileStream to FTP stream 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.UploadFile
Using fileStream As Stream = File.OpenRead("C:\local\path\file.zip"),
ftpStream As Stream = request.GetRequestStream()
fileStream.CopyTo(ftpStream)
End Using
If you need to monitor an upload 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.UploadFile
Using fileStream As Stream = File.OpenRead("C:\local\path\file.zip"),
ftpStream As Stream = request.GetRequestStream()
Dim read As Integer
Do
Dim buffer() As Byte = New Byte(10240) {}
read = fileStream.Read(buffer, 0, buffer.Length)
If read > 0 Then
ftpStream.Write(buffer, 0, read)
Console.WriteLine("Uploaded {0} bytes", fileStream.Position)
End If
Loop While read > 0
End Using
For GUI progress (WinForms ProgressBar), see C# example at:
How can we show progress bar for upload with FtpWebRequest
If you want to upload all files from a folder, see C# example at
Upload directory of files to FTP server using WebClient.
