.IsValidEmail() reporting incorrect results

[jasenf]

String extension method .IsValidEmail() is incorrectly reporting e-mails such as

username+something@domain.com

as invalid. This is a valid RFC e-mail address, and one recommended by Google to alias existing inboxes.

[JonathanMagnan]

Hello @jasenf ,

Do you have a proposal to the Regex we should use? Last time I made a research about it, pretty much all regex has some flaw and it seems there is no consensus about which Regex to use.

Best Regards,

Jonathan

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Performance Libraries
context.BulkInsert(list, options => options.BatchSize = 1000);
Entity Framework Extensions • Entity Framework Classic • Bulk Operations • Dapper Plus

Runtime Evaluation
Eval.Execute("x + y", new {x = 1, y = 2}); // return 3
C# Eval Function • SQL Eval Function

[jasenf]

I think it's fine as-is if you just allow the + sign.

[JonathanMagnan]

We will try to review it soon by using the syntax from here: https://en.wikipedia.org/wiki/Email_address

It will not be perfect but we will change the regex to at least contains printable characters (which contains the plus sign)

[dmarciano]

If you really want to make it validate email addresses, RegularExpressions probably isn't the way to go. The simplest way to cover everything would probably be to just try creating a new MailAddress object and catch if an exception is thrown OR re-implement the code that does the email address validation from the .NET framework (https://github.com/microsoft/referencesource/blob/master/System/net/System/Net/mail/MailAddressParser.cs)