Adding DataAnnotation Check to Internal Property

Is it possible to check for an internal property that has a data annotation?

For example:

public class Customer
{
    [Required, Range(1, int.MaxValue)]
    internal int CustomerID { get; set; }
}

      

        
        
        
      

    

When checking use

Validator.TryValidateObject(customerInstance, new ValidationContext(customerInstance), null, true);

      

        
        
        
      

    

It doesn't check the internal field. I assume this is because the assembly " System.ComponentModel.DataAnnotations

" knows nothing about the internals of my assembly.

I tried to make the DataAnnotation assembly a "Friend" assembly with the following expression before the Customer class:

[assembly: InternalsVisibleTo("System.ComponentModel.DataAnnotations, PublicKey=0024000004.....")]

      

        
        
        
      

    

but it doesn't work.

The reason I am doing an internal customer CustomerID is because nothing outside of my assembly needs to know about it.