I use this
@\"^([\\w\\.\\-]+)@([\\w\\-]+)((\\.(\\w){2,3})+)$\"
regexp to validate the email
([\\w\\.\\-]+)
- this is f
I have an expression for checking email addresses that I use.
Since none of the above were as short or as accurate as mine, I thought I would post it here.
@"^[\w!#$%&'*+\-/=?\^_`{|}~]+(\.[\w!#$%&'*+\-/=?\^_`{|}~]+)*"
+ "@"
+ @"((([\-\w]+\.)+[a-zA-Z]{2,4})|(([0-9]{1,3}\.){3}[0-9]{1,3}))$";
For more info go read about it here: C# – Email Regular Expression
Also, this checks for RFC validity based on email syntax, not for whether the email really exists. The only way to test that an email really exists is to send and email and have the user verify they received the email by clicking a link or entering a token.
Then there are throw-away domains, such as Mailinator.com, and such. This doesn't do anything to verify whether an email is from a throwaway domain or not.