I have been trying to add validation attributes dynamically at runtime and all works ok.

I next tried to add a DisplayAttribute at runtime hooking into the same

public class CustomModelValidatorProvider : DataAnnotationsModelValidatorProvider
    {
        protected override IEnumerable<ModelValidator> GetValidators(ModelMetadata metadata, ControllerContext context, IEnumerable<Attribute> attributes)
        {
            List<Attribute> newAttributes = new List<Attribute>(attributes);


            if (!string.IsNullOrWhiteSpace(metadata.PropertyName) && metadata.PropertyName == "LastName")
            {
                //add a new one -WORKS!
                StringLengthAttribute attr = new StringLengthAttribute(25);
                attr.MinimumLength = 2;
                newAttributes.Add(attr);
            }


            if (!string.IsNullOrWhiteSpace(metadata.PropertyName) && metadata.PropertyName == "City")
            {
                //add a new one - does not work
                DisplayAttribute attr = new DisplayAttribute();
                attr.Name = "The Big City";
                newAttributes.Add(attr);
            }


            return base.GetValidators(metadata, context, newAttributes);
        }
        

    }