在Entity Framework代码优先方法中，两个字段的组合必须唯一。会怎么样？

Question

我有两个班级联系人和组结合FirstName和LastName必须是唯一的，可以为单个联系人添加多个地址。如何在实体框架代码优先方法中做到这一点？public class Contacts{    [Key]    public int ContactID { get; set; }    [ForeignKey("Group")]    public int GroupID { get; set; }    [Required]    public string FirstName { get; set; }    [Required]    public string LastName { get; set; }    [Required]    public string Address { get; set; }    [Required]    public string Number { get; set; }    [Required]    [EmailAddress]    public string EmailId { get; set; }    [DataType(DataType.Date)]    public DateTime CreateDate { get; set; }    public DateTime? ModifiedDate { get; set; }    public virtual Groups Group { get; set; }}public class Groups{    [Key]    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]    public int GroupID { get; set; }    [Required]    public string GroupName { get; set; }    [Required]    public string GroupDiscription { get; set; }    public DateTime CreateDate { get; set; }    public DateTime ModifiedDate { get; set; }}