Question

I want to extend the standard asp.net email regex validator to exclude a specific email.

This is the original:

 ValidationExpression="(\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*)" 

This is the extended that I produced:

 ValidationExpression="(\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*)|(?!^email\@email\.com$)" 

Can’t figure out why this doesn’t work

P.s. I know that the standard asp.net regex validator is not recommended for email validation, but it is OK for me.

Answer 1

^(?!^email@email\.com$)[originalregexhere]

This is doing a negative lookahead right at the beginning of the matching.

The full example:

ValidationExpression="(?!^email@email\.com$)(\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*)"