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

Since anyone who is using custom validation attributes and also wants to load error messages from resources for localization purposes, would face this problem i share my workaround here.
assume that you have a custom validation attribute like this one

[FileTypeMustBe("jpg")]
public HttpPostedFileBase MyFile {get; set;}

in your custom validation attribute add this code

public override string FormatErrorMessage(string name)
    {
        return String.Format(CultureInfo.CurrentCulture,
          ErrorMessageString, name, ValidFileType);
    }

ValidFileType is name of a property which takes the input argument of custom validation attribute (jpg here),well now we can decorate our model property the way we like it to be

[FileTypeMustBe("jpg", ErrorMessageResourceType = typeof(Resources.Resources), ErrorMessageResourceName = "WrongFileTypeError")]
public HttpPostedFileBase MyFile {get; set;}

as you see there's no need to add ErrorMessage=null anymore cause we took care of it in custom validation class. just do not forget if you had initialized any error message string in your custom validation , you have to remove it now and use FormatErrorMessage instead.