CODEWITHSUNDEEP
c#wpfregexdata-annotations
Geo242
Geo242

Reputation: 597

Regex DataAnnotation in WPF

I can't figure out why this regular expression doesn't work the way I want it to. I want it to allow something like this: "Test123#%&*- Test"

[RegularExpression("[^a-zA-Z0-9/#%&*\\- ]")]

The MSDN documentation only gives one example...

[RegularExpression(@"^[a-zA-Z''-'\s]{1,40}$")]

I don't want to limit input to any specific character length, which the MSDN example does do. I have used this regex pattern with the Regex object in .net and it works just fine. Why would the DataAnnotations work differently?

Upvotes: 0

Views: 897

Answers (2)

Ellesedil
Ellesedil

Reputation: 1626

Regex DataAnnotations is written in a way to find what is valid, rather than finding what is invalid. You WANT to match with valid values.

MSDN Link

I'd drop your carrot (^). This will allow each individual character you supply to be validated. If anything fails, you'll generate your error message.

Upvotes: 0

stema
stema

Reputation: 92976

I think your way of using a negated class to find not allowed characters is wrong. I can't find a documentation to prove it, but it seems logical to me.

I think you need to give a pattern that matches the allowed input.

Try

[RegularExpression("^[a-zA-Z0-9/#%&*\\- ]*$")]

The * quantifier makes it repeat the character class 0 or more times. This allows also the empty string! If you don't want the empty string use the quantifier +, that would be one or more.

* is a shortcut for {0,}. if you omit the second number it means there is no maximum match

+ is a shortcut for {1,}.

Upvotes: 1

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