Dim extensions As String() = New String(0) {"*.txt"}
Dim dir As New IO.DirectoryInfo(myExport)
Dim files() As IO.FileInfo = GetFiles(dir, extensions)
 
Array.Sort(files, New FileComparer)
 
ListBox1.Items.AddRange(files)
ListBox1.DisplayMember = "Name"

Class FileComparer
    Implements IComparer(Of FileInfo)
 
    Public Function Compare(ByVal x As FileInfo, ByVal y As FileInfo) As _
      Integer Implements IComparer(Of FileInfo).Compare
 
        '".txt" entfernen
        Dim xName As String = x.Name.Substring(x.Name.LastIndexOf("."))
        Dim yName As String = x.Name.Substring(x.Name.LastIndexOf("."))
 
        Dim xVal As Integer
        Dim yVal As Integer
 
        'Name als Zahl interpretieren
        If Integer.TryParse(xName, xVal) AndAlso Integer.TryParse(yName, yVal) _
          Then
            Return xVal.CompareTo(yVal)
 
        Else
            'Namen können nicht als Zahlen interpretiert werden.
            Return String.Compare(x.Name, y.Name)
 
        End If
    End Function
 
End Class