ftp connection and upload what happens to connection if there is exception - vb.net

Question

Below is code for how you can upload a file using ftp. My question is what happens if there is an exception in the try, will the ftp connection automatically close in the catch? Is it better to use a "using"?
thank you
Try
'connect to ftp server
Dim ftp As New FTPConnection
ftp.ServerAddress = "ftp.example.com"
ftp.UserName = "example_user"
ftp.Password = "example_pass"
ftp.Connect()
ftp.TransferType = FTPTransferType.BINARY
'upload a file
ftp.UploadFile("s:\test.txt", "test.txt")
'close the connection
ftp.Close()
Catch ex As Exception
MessageBox.Show(ex.Message.ToString())
End Try

Answer 1

When an exception happens (whatever it is) the control flow skips everything until it arrives to a Catch instruction.
So in this case if you have an exception in the UploadFile you will not close the connection.
If the FTPConnection class is IDisposable then your best option is to use the using keyword. Otherwise use the finally statament after the Catch as Grant said.

Answer 2

No, it won't close if an exception occurs before ftp.Close() has finished executing. You should use a Finally block to make sure that ftp is always closed, even if an exception occurs. This means you should define ftp at a higher scope level than within the try block, so that it is accessible within the finally block. You could technically call Close from within the catch block but that A) won't cover both/all circumstances and B) might not work anyway if code in the catch throws yet another exception.
Dim ftp As New FTPConnection
Try
Catch ex As Exception
MessageBox.Show(ex.Message.ToString())
Finally
ftp.Close()
End Try