Question

I am starting an MVC project and designing my DB in EF, which means I design the tables, and VS creates the classes I need to access them.

The problem is, I want to make use of attributes like DisplayName, Required and generating validation error messages ( including specifying rules to validate ).

As far as I can see, the classes are recreated every time I change my DB, so I can’t really add them to the classes. Is there another way to do this once and have it persist ?

Answer 1

So you would use the MetadataType attribute and link your entity to a type where you’ll set the validation attributes.

Something like this for an Entity Person:

[MetadataType(typeof(Person_Validation))]//<<link to metadata class
public partial class Person//<<<Your real entity class
{//this is in a separate file.
  //note =>partial. There's nothing in this class
}
public class Person_Validation//the validations go here.
{
        [StringLength(255, ErrorMessage="Name is required"), Required]
        [DisplayName("Name")]
        public string Name { get; set; }
}