Ah ... allora puoi prendere ad esempio queste righe per le tue conversioni

codice:
        Dim i As Integer
        Dim s As String

        i = Convert.ToInt32("23", 8)
        Console.WriteLine(i.ToString())

        s = Convert.ToString(i, 8)
        Console.WriteLine(s)

        i = Convert.ToInt32("1011", 2)
        Console.WriteLine(i.ToString())

        s = Convert.ToString(i, 2)
        Console.WriteLine(s)