REGEX rejecting simple alphamumeric

Question

I don't get it; this should be simple:

Why does this text box entry:

Foo 2010

Validated by this REGEX:

ValidationExpression="^[a-zA-Z0-9 -_!]+$"

Throw an invalid entry error? It is intended to allow alphamumerics, spaces, dashes, underscores and exclamation marks.

REGEX gives me a headache ...

Answer 1

The dash - should be placed right after [ or placed before ] or escaped with \,
otherwise it'll be treated as a class range metacharacter.

Try this: ValidationExpression="^[-a-zA-Z0-9 _!]+$"