I am already using Enterprise Library 5 Validation for my model (which is used also in WCF methods), so I decided that I would like to avoid redundant validators from ASP.NET 4 MVC with DataAnnotations.
But it seems, Enterprise Library Validators are not picked up automatically by MVC.
if I use MVC DataAnnotations:
[RegularExpression(MyValidationExpressions.Email, ErrorMessage = MyValidationMessages.InvalidEmailMessage)]
public virtual string Email { get; set; }
HTML contains data-val-regex-pattern and the field is being validated client-side.
But if I use the existing EL based validation:
[RegexValidator(MyValidationExpressions.Email, MessageTemplate = MyValidationMessages.EmptyFieldMessage))]
public virtual string Email { get; set; }
it does not display validation errors client-side, and the generated HTML does not have any validation attributes.
What am I missing here, how do I force MVC to use the existing EL validators both client-side and server-side?
Solution:
I accepted the solution to move completely to DataAnnotations. It is the easiest way and it works fine with both EntLib 5 and MVC 4. But there is a little catch with ValidationFactory - I had to replace CreateValidatorFromAttributes with CreateValidator and specific flags. See this article for explanation about how DataAnnotations work with ValidationFactory:
CreateValidatorFromAttributes doesn't use DataAnnotations Attributes
Also DataAnnotations have the [Required] attribute which deals nicely with empty strings and strings which contain only spaces. There were some problems on VAB with that.
The reason why this doesn't work is because VAB's RegexValidatorAttribute does not inherit from System.ComponentModel.DataAnnotations.RegularExpressionAttribute, but directly from ValidationAttribute. Because of this MVC doesn't know how to handle it.
There is a way to change the way MVC does this handling, but I don't know how. But why don't you just replace the usage of the RegexValidatorAttribute with DataAnnotations' RegularExpressionAttribute? Validation Application Block 5 is able to handle DataAnnotations` attributes, so if the DataAnnotations attributes are working, just use them.