Public Class FileSharingForm
Private FTPDownloader As New Utilities.FTP.FTPclient

Private Sub FileSharingForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    btnChangeDirectory.Enabled = False
    FTPDownloader.Hostname = txtServer.Text.Trim
    FTPDownloader.Username = txtUsername.Text
    FTPDownloader.Password = txtPassword.Text
End Sub

Private Sub btnHomeDirectory_Click(sender As Object, e As EventArgs) Handles btnHomeDirectory.Click
    FTPDownloader.CurrentDirectory = "/"
    RefreshList()
End Sub

'important: add items to listbox
Private Sub RefreshList()
    ListFTPFiles.Items.Clear()
    Try
        For Each file In FTPDownloader.ListDirectoryDetail()
            ListFTPFiles.Items.Add(file.Filename)
        Next
    Catch ex As Exception
        MessageBox.Show(ex.Message)
    End Try
End Sub