List of custom Object doesn't get saved ASP .NET MVC

Question

I have a list of Columns that i generate in the following code snippets:


public Match CreateColumn(Match match)
        {
            match.Columns = new List<Column>();
            match.Moves = new List<Move>();
            for (int i = 0; i < 7; i++)
            {
                match.Columns.Add(new Column());
            }
            return match;
        }

That is called in the create method below:

public ActionResult Create(Match match)
        {
            match.State = State.InPartenza;
            match.Data = DateTime.UtcNow.ToString("dd-MM-yyyy");
            match.NextTurnPlayer = match.SetNextTurnPlayer();
            match.UsernamePlayer1 = User.Identity.GetUserName();
            if (!ModelState.IsValid || db.Matches.Find(match.Name) != null || string.IsNullOrWhiteSpace(match.Name))
            {
                ModelState.AddModelError("", "This name is already associated to another game");
                return View(match);
            }
            match = match.CreateColumn(match);
            db.Matches.Add(match);
            db.SaveChanges();
            return RedirectToAction("Index");
        }

The problem is that Colums is alway null and never equals to 7, why?

UPDATE

I get the error int he first if condition

public bool PlayerHasOccupied(Match match, int j, int i, int player)
        {
            if (match.Columns.Count > 0 && match.Columns[j].Cells != null && i <= match.Columns[j].Cells.Count)
            {
                return match.Columns[j].Cells[i].Value == player;
            }
            else
            {
                return false;
            }
        }

The error:

System.NullReferenceException: 'Object reference not set to an instance of an object.' Connect4.Models.Match.Columns.get returned null.

UPDATE 2

Match

        public List<Column> Columns { get; set; }
        [Key]
        [Required]
        public string Name { get; set; }
        public string Data { get; set; }
        [Display(Name = "Next turn player")]
        public NextTurnPlayer NextTurnPlayer { get; set; }
        public State State { get; set; }
        public string UsernamePlayer1 { get; set; }
        public string UsernamePlayer2 { get; set; }
        public string Winner { get; set; }/
        public List<Move> Moves { get; set; }

        public int CanWin { get; set; }

Column

public class Column
    {

        public int Id { get; set; }
        public List<Cell> Cells { get; set; }
        public bool IsFull()
        {
            return Cells.Count == 6;
        }
    }

Cell

public class Cell
    {
        [Key]
        public int Value { get; set; }
        
        public bool IsEmpty(int value)
        {
            return !Convert.ToBoolean(value);
        }
    }

UPDATE 3

public class ManageViewModels : DbContext
    {
        public DbSet<Match> Matches { get; set; }
    }

Don't know the rest of the code, but try match = CreateColumn(match); or just make the method as void change the match in there and that's it — Camadas, May 31 '22 at 13:26
where is that happening into index action or hire in the create — spzvtbg, May 31 '22 at 13:36
@Camadas previuvsly i had the method void but it doesn't work — Sebastiano Bortoletti, May 31 '22 at 13:37
When debugging, does match.Columns contains any item before leaving CreateColumns — Hervé, May 31 '22 at 13:40
@SebastianoBortoletti - yes, but where do you face the problem, in other words how do you know that there are no columns inside or the list is null? — spzvtbg, May 31 '22 at 13:43
If I correctly understood, the problem isn't that .Column is empty but it doesn't get saved ? — Hervé, May 31 '22 at 13:43
:) from where you get the match for PlayerHasOccupied method — spzvtbg, May 31 '22 at 13:47
@Hervé Yes, everything is saved except Column and Moves, maybe because they are lists? — Sebastiano Bortoletti, May 31 '22 at 13:47
@spzvtbg I call a method that calls that method, you say this is the error? .... the other values are correct — Sebastiano Bortoletti, May 31 '22 at 13:49
@Hervé Yes I have, from sql server manager I can also see the columns — Sebastiano Bortoletti, May 31 '22 at 13:50
well, could you update your question (change the title, since it's not that the list is null or empty but it doesn't get saved, and include your Match entity code) — Hervé, May 31 '22 at 13:52
like @Hervé says, also check if you can save an empty column in your table — spzvtbg, May 31 '22 at 13:54
only the stuff related to EF, also include the Colum entity as well :) — Hervé, May 31 '22 at 13:58
`match = match.CreateColumn(match);` this is awkwardly bizzare. — Ondrej Tucny, May 31 '22 at 14:01
Your db context must contains all of your entities to convert them as table. Since you haven't add your columns it can't figure out that `List` inside the `Match` entity is related to your entity `Column`. It's like if you had no table `Column` at all. Just include them and you should be fine ```csharp public class ManageViewModels : DbContext { public DbSet Matches { get; set; } // new public DbSet Columns { get; set; } public DbSet Cells { get; set; } // here add all your entites } ``` — Hervé, May 31 '22 at 14:13
@Hervé Thanks for the reply, the methods you entered new don't have to be commented on though, right? — Sebastiano Bortoletti, May 31 '22 at 14:16
no.... i have also to make something this "db.Matches.Add(match);" to add to the database? @Hervé — Sebastiano Bortoletti, May 31 '22 at 14:23
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/245206/discussion-between-sebastiano-bortoletti-and-herve). — Sebastiano Bortoletti, May 31 '22 at 14:23

List of custom Object doesn't get saved ASP .NET MVC

0 Answers0