Can I define properties in partial classes, then mark them with attributes in another partial class?

Question

Is there a way I can have a generated code file like so:

public partial class A 
{
    public string a { get; set; }
}

and then in another file:

public partial class A 
{
    [Attribute("etc")]
    public string a { get; set; }
}

So that I can have a class generated from the database and then use a non-generated file to mark it up?

Answer 1

I've seen something like this done in an article by Scott Guthrie (near the end of it) - didn't try it myself, though.
http://weblogs.asp.net/scottgu/archive/2010/01/15/asp-net-mvc-2-model-validation.aspx

[MetadataType(typeof(Person_Validation))]
public partial class Person
{
    // Partial class compiled with code produced by VS designer
}

[Bind(Exclude="ID")]
public class Person_Validation
{
    [Required(ErrorMessage = "First Name Required")]
    [StringLength(50, ErrorMessage = "Must be under 50 characters")]
    public string FirstName { get; set; }

    [Required(ErrorMessage = "Last Name Required")]
    [StringLength(50, ErrorMessage = "Must be under 50 characters")]
    public string LastName { get; set; }

    [Required(ErrorMessage = "Age Required")]
    [Range(0, 120, ErrorMessage = "Age must be between 0 and 120")]
    public int Age { get; set; }

    [Required(ErrorMessage = "Email Required")]
    [Email(ErrorMessage = "Not a valid email")]
    public string Email { get; set; }
}