Regex.Matches Idn

Question

Hello

I'm using this to collect emails from string:

Dim mc As MatchCollection = Regex.Matches(src, "([a-zA-Z0-9_\-\.]+)@([a-zA-Z0-9_\-\.]+)\.([a-zA-Z]{2,9})", RegexOptions.CultureInvariant Or RegexOptions.IgnoreCase Or RegexOptions.Multiline)

This will not work on Idn domains, however, there's a validator sample here:

https://learn.microsoft.com/en-us/dotnet/standard/base-types/how-to-verify-that-strings-are-in-valid-email-format

How can I get regex matches and assign to MatchCollection for Idm domains using the above mentioned regex which is:

"^[^@\s]+@[^@\s]+\.[^@\s]+$"

Thanks :)

Answer 1

To support more forms of e-mails, try this pattern (in VB):

"([\p{L}\p{N}_\-\.]+)@([\p{L}\p{N}_\-]+[\.\u3002\uFF0E\uFF61])+([\p{L}\p{N}_\-]+)"

If it does not always work, show examples.

Answer 2

To match email addresses that include Internationalized Domain Names (IDNs), you can use a more comprehensive regular expression. The regex you mentioned (^[^@\s]+@[^@\s]+\.[^@\s]+$) is a good start, but it doesn’t cover all the nuances of IDNs.

Here’s an updated version of your code to handle IDNs:

Dim mc As MatchCollection = Regex.Matches(src, "^[^\s@]+@[^\s@]+\.[^\s@]+$", RegexOptions.CultureInvariant Or RegexOptions.IgnoreCase Or RegexOptions.Multiline)

Best Regards.

Jiachen Li

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Answer 3

there is no 100% accurate regex for email. see this

https://fightingforalostcause.net/content/misc/2006/compare-email-regex.php

or this generated one::

https://pdw.ex-parrot.com/Mail-RFC822-Address.html