RegularExpressionAttribute - How to make it not case sensitive for client side validation?

Question

I have a string that I use for client side validation:

private const String regex = @"^(?:\b(?:\d{5}(?:\s*-\s*\d{5})?|([A-Z]{2})\d{3}(?:\s*-\s*\1\d{3})?)(?:,\s*)?)+$"; 

I use this string in my [RegularExpression(regex, ErrorMessage = "invalid")] attribute.

I know that the /i flag for a Javascript regex is used to make it case insensitive, but just tacking it on to the end of my regex (i.e. @"^....$/i" isn't working - the regex validation fails completely, regardless of what is entered (valid or not).

What am I missing?

Answer 1

I created this attribute which allows you to specify RegexOptions. EDIT: It also integrates with unobtrusive validation. The client will only obey RegexOptions.Multiline and RegexOptions.IgnoreCase since that is what JavaScript supports.

[RegularExpressionWithOptions(@".+@example\.com", RegexOptions = RegexOptions.IgnoreCase)] 

C#

public class RegularExpressionWithOptionsAttribute : RegularExpressionAttribute, IClientValidatable {     public RegularExpressionWithOptionsAttribute(string pattern) : base(pattern) { }      public RegexOptions RegexOptions { get; set; }      public override bool IsValid(object value)     {         if (string.IsNullOrEmpty(value as string))             return true;          return Regex.IsMatch(value as string, "^" + Pattern + "$", RegexOptions);     }      public IEnumerable<System.Web.Mvc.ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)     {         var rule = new ModelClientValidationRule         {             ErrorMessage = FormatErrorMessage(metadata.DisplayName),             ValidationType = "regexwithoptions"         };          rule.ValidationParameters["pattern"] = Pattern;          string flags = "";         if ((RegexOptions & RegexOptions.Multiline) == RegexOptions.Multiline)             flags += "m";         if ((RegexOptions & RegexOptions.IgnoreCase) == RegexOptions.IgnoreCase)             flags += "i";         rule.ValidationParameters["flags"] = flags;          yield return rule;     } } 

JavaScript

(function ($) {      $.validator.unobtrusive.adapters.add("regexwithoptions", ["pattern", "flags"], function (options) {         options.messages['regexwithoptions'] = options.message;         options.rules['regexwithoptions'] = options.params;     });      $.validator.addMethod("regexwithoptions", function (value, element, params) {         var match;         if (this.optional(element)) {             return true;         }          var reg = new RegExp(params.pattern, params.flags);         match = reg.exec(value);         return (match && (match.index === 0) && (match[0].length === value.length));     });  })(jQuery); 

This article by Anthony Stevens helped me get this working: ASP.NET MVC 3 Unobtrusive Javascript Validation With Custom Validators