This is a shared function to determine if the format of a user postcode for the particular country is valid. This function covers most of Europe’s countries, but more can be added as needed.
The function uses Regex to match the user’s entered postcode to the pattern in the function. You can get master Regex codes, but then the can have loop hole that user’s get through. To be sure I used each country separately which I feel is more robust. You can add countries Regex pattern from this link where I sourced the regex patterns from. http://unicode.org/cldr/trac/browser/trunk/common/supplemental/postalCodeData.xml
If you need them as well these are the country codes for the world. http://www.worldatlas.com/aatlas/ctycodes.htm
Public Shared Function PostcodeReg(ByVal Country As String,ByVal PostCode As String) As String
Dim PostReg As Regex = Nothing
Select Case Country
Case "GB" 'Great Britain
PostReg = "w*sw*"
Case "AT" 'Austria
PostReg = "/^d{4,5}$/"
Case "BE" 'Belgium
PostReg = "^[1-9]{1}[0-9]{3}$"
Case "HR" 'Croatia
PostReg = "d{5}"
Case "CY" 'Cyprus
PostReg = "d{4}"
Case "CZ" 'Czech Republic
PostReg = "d{3}[ ]?d{2}"
Case "DK" 'Denmark
PostReg = "^([D-d][K-k])?( |-)?[1-9]{1}[0-9]{3}$"
Case "EE" 'Estonia
PostReg = "d{5}"
Case "FI" 'Finland
PostReg = "d{5}"
Case "FR" 'France
PostReg = "^(F-)?((2[A|B])|[0-9]{2})[0-9]{3}$"
Case "DE" 'Germany
PostReg = "b((?:0[1-46-9]d{3})|(?:[1-357-9]d{4})|(?:[4][0-24-9]d{3})|(?:[6][013-9]d{3}))b"
Case "GR" 'Greece
PostReg = "d{3}[ ]?d{2}"
Case "HU" 'Hungary
PostReg = "d{4}"
Case "IT" 'Italy
PostReg = "^(V-|I-)?[0-9]{5}$"
Case "LV" 'Latvia
PostReg = "d{4}"
Case "LT" 'Lithuania
PostReg = "d{5}"
Case "LU" 'Luxembourg
PostReg = "d{4}"
Case "MT" 'Malta
PostReg = "[A-Z]{3}[ ]?d{2,4}"
Case "NL" 'Netherlands
PostReg = "^[1-9][0-9]{3}s?([a-zA-Z]{2})?$"
Case "PL" 'Poland
PostReg = "d{2}-d{3}"
Case "PT" 'Portugal
PostReg = "d{4}([-]d{3})?"
Case "RO" 'Romania
PostReg = "d{6}"
Case "SK" 'Slovakia
PostReg = "d{3}[ ]?d{2}"
Case "SI" 'Slovenia
PostReg = "d{4}"
Case "ES" 'Spain (exc. Canary Islands)
PostReg = "^([1-9]{2}|[0-9][1-9]|[1-9][0-9])[0-9]{3}$"
Case "SE" 'Sweden
PostReg = "^(s-|S-){0,1}[0-9]{3}s?[0-9]{2}$"
End Select
Dim PostMatch As Match = PostReg.Match(PostCode )
If PostMatch.Success Then
''True
Else
''False
End If
Return PostMatch.Success
End Function
