io invece posto il check del codice fiscale in una piccolissima sub:
B4X:
Sub checkcode(s As String) As Boolean
If s.Length <> 16 Then
Return False
End If
For x = 0 To s.Length - 1
Dim ss As String = s.SubString2(x, x + 1)
Select Case x + 1
Case 1, 2, 3, 4, 5, 6, 9, 12, 16
If IsNumber(ss) = True Then
Return False
End If
Case 7, 8, 10, 11, 13, 14, 15
If IsNumber(ss) = False Then
Return False
End If
End Select
Next
Return True
End Sub