CODEWITHSUNDEEP
c#regexasp.net-mvc-3
Daniel
Daniel

Reputation: 169

Regex for disallowing commas

I'm trying to disallow commas in a string entered into a textbox. Here is what I have so far:

[RegularExpression (@"?[^,]*$",
        ErrorMessage = "Commas are not allowed in the subtask title. Please remove any and try again")]

This is probably my 5th or 6th attempt, nothing so far has worked. Any help would be appreciated.

Upvotes: 7

Views: 19419

Answers (1)

Kelvin
Kelvin

Reputation: 5307

Try changing your regex to:

"^[^,]+$"

Let's say we're matching against "Hello, world"

The first ^ asserts that we're at the beginning of the string. Next [^,] is a character class which means "Any character except ,." + next to something means "Match this one or more times." Finally, $ asserts that we're now at the end of the string.

So, this regular expression means "At the start of the string (^), match any character that's not a comma ([^,]) one or more times (+) until we reach the end of the string ($).

This regular expression will fail on "Hello, world" - everything will be fine for H, e, l, l, and o, until we reach the comma - at which point the character class fails to match "not a comma".

For some great tutorials about regular expressions, you should read up on http://www.regular-expressions.info/

Upvotes: 25

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