Negating a regex for use MVC validation attributes

Question

Can we negate this expression, if no match found to return true for use in regex attributes (MVC dataannotations)?

Pattern should match:

I want to negate this expression/pattern

[RegularExpression(@"^(.{0,7}|[^0-9]*|[^A-Z]*|[a-zA-Z0-9]*)$")]

I tried ?! with no success:

[RegularExpression(@"^(?!.{0,7}|[^0-9]*|[^A-Z]*|[a-zA-Z0-9]*)$")]

You can try `"^(?!(?:.{0,7}|[^0-9]*|[^A-Z]*|[a-zA-Z0-9]*)$).*$"`. — Wiktor Stribiżew, Apr 16 '16 at 12:16
@WiktorStribiżew, passive non capturing group was the missing part. Thank you it works! You can post it as an answer and i will accept it. — Legends, Apr 16 '16 at 12:42

score 2 · Accepted Answer · answered Apr 16 '16 at 12:46

To negate an expression containing several anchored alternatives, you need to group them inside an anchored negative lookahead.

Thus, just add a group (either capturing or non-capturing):

"^(?!(?:.{0,7}|[^0-9]*|[^A-Z]*|[a-zA-Z0-9]*)$).*$"

Since a RegularExpressionAttribute needs a full string match, I added .*$.

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