Public Shared Function checkserial(ByVal seriennummer As String) As Boolean
        Dim serial(1), s As String
        Dim a(1) As String
        a(0) = "xxxxx-12345-1234x-12345"
        a(1) = "xxxxx-x2345-x1234-6543x"
 
        Dim c As Char
        Dim b As Boolean = False
        Dim i As Int16 = 0
        For Each s In a
            serial(0) = s
            serial(1) = seriennummer
            i = 0
            For Each c In s
                If c = "x" Then
                    serial(1) = serial(1).Remove(i, 1)
                    i -= 1
                End If
                i += 1
            Next
            If serial(1) = serial(0).Replace("x", "") Then
                b = True
            End If
        Next
        Return b
    End Function

        If checkserial("12345-12345-12345-12345") Then
            'Hier der Code der ausgeführt werden soll wenn die serial ok ist
        Else
            'Hier wenn nicht
        End If