1つのアクションに新しい関連エンティティを追加する

Question

すべての謎には1つ以上の質問があります。どのように1つのフォームを送信してその謎に謎と質問の両方を追加できますか？

このRiddlesControllerはアクションコードを作成している：

public ActionResult Create(RiddleViewModel model) 
     { 
      if (ModelState.IsValid) 
      { 
       try 
       { 
        _db.Riddles.Add(new Models.Riddle 
        { 
         Name = model.Name, 
         Description = model.Description , 
         CreationDate = DateTime.Now, 
         User = _db.Users.Find(User.Identity.GetUserId()), 
        }); 
        _db.Questions.Add(new Models.Question 
        { 
         Body = model.FirstQuestionBody, 
         Answer = model.FirstQuestionAnswer, 
         CreationDate = DateTime.Now, 
         // What should I write here? or is there any better way to accomplish this? 
         Riddle = ????? 
        }); 
        _db.SaveChanges(); 
        return RedirectToAction("Index"); 
       } 

       catch 
       { 
        return View(); 
       } 
      } 
      return View(); 
     } 

これは、謎のモデルコードです：

public class Riddle 
{ 
    public int Id { get; set; } 
    public string Name { get; set; } 
    [MaxLength(200)] 
    [DataType(DataType.MultilineText)] 
    public string Description { get; set; } 
    public List<Review> Reviews { get; set; } 
    [Required] 
    public ApplicationUser User { get; set; } 
    public virtual List<Question> Questions { get; set; } 
    [Column(TypeName = "datetime2")] 
    public DateTime CreationDate { get; set; }  

} 

これは質問のモデルコードです：

public class Question 
    { 
     public int Id { get; set; } 
     public string Body { get; set; } 
     public string Answer { get; set; } 
     public Riddle Riddle { get; set; } 
     [Column(TypeName ="datetime2")] 
     public DateTime CreationDate { get; set; } 
    } 

これはRiddleViewModelコードです：

public class RiddleViewModel 
    { 
     [Required] 
     public string Name { get; set; } 
     [MaxLength(200)] 
     [DataType(DataType.MultilineText)] 
     public string Description { get; set; } 
     // Question properties 
     [DataType(DataType.MultilineText)] 
     public string FirstQuestionBody { get; set; } 
     public string FirstQuestionAnswer { get; set; } 
    } 

Answer 1

次のように試すことができます。

_db.Questions.Add(new Models.Question 
        { 
         Body = model.FirstQuestionBody, 
         Answer = model.FirstQuestionAnswer, 
         CreationDate = DateTime.Now, 
         Riddle = new Models.Riddle 
            { 
            Name = model.Name, 
            Description = model.Description , 
            CreationDate = DateTime.Now, 
            User = _db.Users.Find(User.Identity.GetUserId()), 
            } 
         }); 

        _db.SaveChanges();