Either ErrorMessageString or ErrorMessageResourceName must be set, but not both error using CreditCardAttribute

Question

This is my model:

namespace MvcApplication2.Models
{
    public class CreditCard
    {
        [CreditCard(ErrorMessageResourceType = typeof(Messages), Error         


        

Answer 1

Replacing

[Required(ErrorMessage = "")]

with

[Required()]

worked for me, there is no meaning of keeping ErrorMessage with a blank string either