Public Class frmFileList
 
    Dim WithEvents btnFolder As New Button With
         {.Parent = Me, .Width = 300, .Text = "Ordner wählen"}
 
    Dim bsFolder As New BindingSource
 
    Dim lboFiles As New ListBox With
         {.Parent = Me, .Width = 400, .Top = 50, .Height = 300,
         .DataSource = bsFolder, .HorizontalScrollbar = True}
 
 
    Dim _folder As String = ""
    Dim _files As New List(Of String)
    Dim _errors As New List(Of String)
 
 
    Private Sub frmFileList_Load(sender As Object, 
                                 e As EventArgs) Handles Me.Load
 
        Me.Size = New Size(420, 400)
        Me.FormBorderStyle = FormBorderStyle.FixedDialog
    End Sub
 
 
    Private Sub btnFolder_Click(sender As Object, 
                                e As EventArgs) Handles btnFolder.Click
 
        Using fbd As New FolderBrowserDialog
            With fbd
                .Description = "Ordner angeben"
                .ShowNewFolderButton = False
                .SelectedPath = _folder
                If .ShowDialog() = DialogResult.Cancel Then Exit Sub
 
                _folder = .SelectedPath
                btnFolder.Text = _folder
 
                _errors.Clear() : _files.Clear()
                Me.Enabled = False
 
                Getfiles(New IO.DirectoryInfo(_folder), "*.txt", 
                                              _files, _errors)
 
                Me.Enabled = True
 
                bsFolder.DataSource = _files
                bsFolder.ResetBindings(False)
            End With
        End Using
    End Sub
End Class