public class Game
    {
        [Key]
        public Guid Id { get; set; }

        [DisplayName("游戏名称")]
        [Required(ErrorMessage = "{0}不能为空")]
        public string Name { get; set; }


        [DisplayName("添加时间")]
        public DateTime AddDate { get; set; }

        public ICollection<GameZone> GameZones { get; set; }
    }

public class GameZone
    {
        [Key]
        public Guid Id { get; set; }

　　　　public Guid GameID{get;set}
        [DisplayName("游戏名称")]
        public Game Game { get; set; }

        [DisplayName("游戏区名称")]
        [Required(ErrorMessage = "{0}不能为空")]
        public string Name { get; set; }

    }

public ActionResult Edit([Bind(Include = "Id,Name,Game,AddDate")] GameZone gamezone)
        {
            
            if (ModelState.IsValid)
            {
                gamezone.Game = _db.Games.Find(gamezone.Game.Id);
                gamezone.AddDate = DateTime.Now;
                _db.Entry(gamezone).State = EntityState.Modified;
                _db.SaveChanges();
                return RedirectToAction("Index");
            }
            return View(gamezone);
        }