Dim S As String = _
        "Hallo," & vbNewLine & _
        "das ist ein:" & vbNewLine & _
        "Test" & vbNewLine & _
        "Hoffentlich klappt es!"
        'S hat 4 Zeilen
        Dim subS As String = S
        Dim i As Integer = 1
        Do Until subS.IndexOf(vbNewLine) = -1
            subS = subS.Substring(subS.IndexOf(vbNewLine) + 1)
            i = i + 1
        Loop
        Console.WriteLine(i)