Question

This is my ViewModel:

 public class PlayerViewModel
    {
        PlayerRepository repo = new PlayerRepository();

        public Player Player { get; set; }
        public int SelectedUserID { get; set; }
        public SelectList Users { get; set; }


        public PlayerViewModel()
        {
            Player = new Player();
        }
        public PlayerViewModel(Player player)
        {
            Player = player;

            SelectedUserID = 0;
        }
   }

This is in my controller (it´s for editing):

    [Authorize]
    public ActionResult Upravit(int id)
    {

        var player = repo.Retrieve(id);
        var playerView = new PlayerViewModel(player);
        playerView.Users = new SelectList(repo.GetUsers(), "UserID", "UserName");
        return View(playerView);
    }
    [Authorize,HttpPost]
    public ActionResult Upravit(int id, PlayerViewModel playerView)
    {
        if (ModelState.IsValid)
        {
            playerView.Player.User = repo.GetUserByID(playerView.SelectedUserID);

            repo.Save(playerView.Player);
            return RedirectToAction("Podrobnosti", new { id = playerView.Player.PlayerID });
        }
        return View(playerView);
    }

and repo:

public User GetUserByID(int id)
        {
            return db.Users.Find(id);
        }

public int Save(Player player)
    {
        db.Entry(player).State = player.PlayerID == 0 ?
            EntityState.Added : EntityState.Modified;
        db.SaveChanges();
        return player.PlayerID;
    }

My problem is that I get in httppost valid viewmodel, I add User to player (it´s custom class and in player class it´s virtual User User) and in debug it looks everything ok (player contains right user) but nexttime when I in other view try to retrieve player it´s property with User is null. I checked it in database and there is no int in column with UserID. So maybe somebody can help me where is problem? Why it´s not saving?

Edit:
I added this code to my repository:

private bool disposed = false;

        protected virtual void Dispose(bool disposing)
        {
            if (!this.disposed)
            {
                if (disposing)
                {
                    db.Dispose();
                }
            }
            this.disposed = true;
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

and change in controller to this:

[Authorize,HttpPost]
        public ActionResult Upravit(int id, PlayerViewModel playerView)
        {
            if (ModelState.IsValid)
            {
                using (PlayerRepository playerRepository = new PlayerRepository())
                {
                    playerView.Player.User = playerRepository.GetUserByID(playerView.SelectedUserID);

                    playerRepository.Save(playerView.Player);
                    return RedirectToAction("Podrobnosti", new { id = playerView.Player.PlayerID });
                }
            }
            return View(playerView);
        }

but it didn´t help.

Edit2
My player and User classes:

 public class User
 {
    public User()
    {
    }
    public User(int userId, string userName, string firstName, string surname, string password, string email)
    {
        UserID = userId;
        UserName = userName;
        Name = firstName;
        Surname = surname;
        Password = password;
        Email = email;
        IsActivated = false;
    }

    [HiddenInput(DisplayValue = false)]
    public int UserID { get; set; }

    [Display(Name="Uživatelské jméno")]
    [Required(ErrorMessage = "Je potřeba vyplnit uživatelské jméno.")]
    [StringLength(20)]
    public string UserName { get; set; }

    public string Name { get; set; }

    public string Surname { get; set; }
    [Display(Name = "Heslo")]
    [DataType(DataType.Password)]
    [Required(ErrorMessage = "Je potřeba vyplnit heslo.")]
    [StringLength(30)]
    public string Password { get; set; }

    [Display(Name = "E-mail")]
    [DataType(DataType.EmailAddress)]
    [Required(ErrorMessage = "Je potřeba vyplnit Váš e-mail.")]
    [StringLength(30)]
    public string Email { get; set; }
    public IIdentity Identity { get; set; }

    public string ImagePath { get; set; }

    public virtual ICollection<Article> Articles { get; set; }
    public virtual ICollection<Comment> Comments { get; set; }
    public virtual ICollection<Post> Posts { get; set; }
    public virtual ICollection<Topic> Topics { get; set; }

    public int RoleId { get; set; }
    public virtual Role Role { get; set; }

    public bool IsActivated { get; set; }
    public string EmailKey { get; set; }
}
}

 public class Player
{
    [Key]
    public int PlayerID { get; set; }

    [Required]
    public string Name { get; set; }
    [Required]
    public string Surname { get; set; }

    public string PhotoUrl { get; set; }

    public string Post { get; set; }

    public virtual Team Team { get; set; }

    public virtual User User { get; set; }
}

I added using with repo to every method in Controller and added Dispose method on controller and now I have problem with showing data. For example when I tried showing Player.User.UserName (I have manually added some users to players) It says that instance ObjectDataContext was dispose and cant be used.

Answer 1

It seems it is necessary to dispose the ObjectContext; otherwise there are a different ObjectContext instances each time, you can run into problems when doing queries among objects of the contexts.

Implement IDisposable for your Repository class: call the Dispose method for underlying ObjectContext class instance.

Client code:

using (PlayerRepository playerRepository = new PlayerRepository())
{
    // Perform queries, etc.
}

Update

To simplify disposing of the repository, just override Dispose method of Controller-derived class: call Dispose for the repository here. The ASP.NET MVC framework will automatically call Controller.Dispose() at the end of the request.

Update

It is necessary to define property called <entity>Id to define the relationship.

public class Player
{
    // Having a property called <entity>Id defines a relationship.
    public int UserId { get; set; }
    public virtual User User { get; set; }
}

Hope this helps.