使用数据注释进行模型验证的错误消息

Given the following classes:

鉴于以下类别：

using System.ComponentModel.DataAnnotations;

public class Book{
   public Contact PrimaryContact{get; set;}
   public Contact SecondaryContact{get; set;}

   [Required(ErrorMessage="Book name is required")]
   public string Name{get; set;}
}
public class Contact{
    [Required(ErrorMessage="Name is required")]
    public string Name{get; set;}
}
using