Parameterising resource strings in Required attribute in Data Annotations

Question

I hope the subject made sense :)

I'm not fussed about local/global stuff but if I have a resource named IsRequired with a value of "{0} is required." how to use with Data Annotations? (not MVC btw)

This will "work", of course:

[Required(ErrorMessageResourceName = "IsRequired", 
ErrorMessageResourceType=typeof(Resources))]

But I'd need something like:

[Required(string.Format(ErrorMessageResourceName = IsRequired, "MyProperty"), 
ErrorMessageResourceType=typeof(Resources))]

(yes I know that won't work ;)

Is it possible to format the resource string in a data annotation required attribute? Why write 200 required resource strings when 1 will suffice?

Thanks, Richard

Related question: http://stackoverflow.com/questions/3089760/using-asp-net-mvc-data-annotation-outside-of-mvc — M.Babcock, Feb 07 '12 at 01:20

score 1 · Answer 1 · answered Feb 07 '12 at 01:26

One option is to subclass RequiredAttribute:

public class MandatoryAttribute : RequiredAttribute
{
    // ...
}

You can then override the Validate method, in which you can inspect the ValidationContext for the property name and use that to produce the correct error message.

Parameterising resource strings in Required attribute in Data Annotations

1 Answers1