Case Insensitive Compare with Fluent Validation

Question

I have been unsuccessful in implementing case insensitive comparing using Fluent Validations. I am just trying to compare two email fields and ignoring case.

The rules in place currently are:

RuleFor(x => x.EmailAddress).NotEmpty().Length(5, 200).EmailAddress();
RuleFor(x => x.ConfirmEmailAddress).NotEmpty().Equal(x => x.EmailAddress).WithMessage("Emails must match");

To add the requirement to be case insensitive I considered passing a comparer with the equal call but that does not seem to work.

RuleFor(x => x.ConfirmEmailAddress).NotEmpty().Equal(x => x.EmailAddress, StringComparer.CurrentCultureIgnoreCase).WithMessage("Emails must match"); 

Ideally, I would like to have a case insensitive comparison done on client side if possible. Will anyone be able to provide guidance on how to accomplish this?

The NuGet packages I am currently using are:

<package id="FluentValidation" version="5.1.0.0" targetFramework="net45" />
<package id="FluentValidation.MVC4" version="5.1.0.0" targetFramework="net45" />

Answer 1

You can make use of the .Must() extension method, with the overload that accepts both the parent object and the property being validated like so:

RuleFor(x => x.ConfirmEmailAddress)
    .NotEmpty()
    .Must((x, confirmEmailAddress) => x.EmailAddress.Equals(confirmEmailAddress, StringComparison.OrdinalIgnoreCase))
    .WithMessage("Emails must match");

This is only supported on the server-side, however, as per the documentation:

Note that FluentValidation will also work with ASP.NET MVC's client-side validation, but not all rules are supported. For example, any rules defined using a condition (with When/Unless), custom validators, or calls to Must will not run on the client side. The following validators are supported on the client:

• NotNull/NotEmpty
• Matches (regex)
• InclusiveBetween (range)
• CreditCard
• Email
• EqualTo (cross-property equality comparison)
• Length