Question

In MVC3 how would I create a custom attribute to a strongly defined class (apologies about terminology, I’m learning as I go here) so that I can use it like:

[CustomValue(AttributeMappingName = "first.name")]

I would like to be able to display ‘first-name’ within my view, I realise this is static for every Patient_FirstName but I wish to access a custom mappingname client side.

Context:

public class FormStandard_Model
    {
        [Required()]
        [Key]
        public string My_ID { get; set; }

        [Required]
        [StringLength(32, MinimumLength = 2)]
        [Display(Name = "First Name")]
        [CustomValue(AttributeMappingName =  "first.name")]
        public string Patient_FirstName { get; set; }

    }

Answer 1

Sounds like you need to create a custom ModelMetadataProvider so that the data in your custom attribute will be available in your view. See this answer:
Custom Data Annotations ASP.NET MVC C#