Dim postcode2 As String
    Dim arraynummer As Integer
    Dim selecteditem As Integer

arraynummer = 0
        aantal = Lijst1.Items.Count

        Dim postcodes(aantal - 1) As String

        Lijst1.Items.CopyTo(postcodes, 0)
        Array.Sort(postcodes)

        For x = 0 To postcodes.Length - 1
            Lijst2.Items.Add(postcodes(x))
        Next x