C＃基类具有派生类成员，并且会循环

Question

I have this class:

public class GameData
{
    public int[,] mat { get; set; }
    public int dim { get; set; }
    public int goal { get; set; }
    public Game game { get; set; }

    public GameData()
    {
        game = new Game();
    }
}

And this two other derived classes:

public class Game :GameData
{
    private Mover m;

    public Game()
    {
        dim = 4;
        goal = 16;
        mat = new int[dim, dim];
        m = new Mover();
    }
    /*Methods*/
}

public class Mover : GameData
{
    /*Methods*/
}

It loops because Game constructor calls GameData constructor and so on. How can I do? I am starting whit OOP programming and I am not sure this three classes are the best way to set the program. GameData contains common datas, Game contains the method to play and Mover contains a group of method used by Game

Answer 1

Honestly inheritance doesn't make any sense here. Inheritance is an "is a type of" relationship (in other words, is Game a type of GameData ? I doubt it.

Instead use composition! Just have class hold the objects they care about. Composition is a "has a" relationship, which makes a lot more sense in your case. Honestly, I would invert the Game / GameData relationship, a Game probaly holds GameData ; not the other way around. Only you know what you need though.

public class GameData
{
    public int[,] mat { get; set; }
    public int dim { get; set; }
    public int goal { get; set; }
    public Game game { get; set; }

    public GameData()
    {
        game = new Game();
        dim = 4;
        goal = 16;
        mat = new int[dim, dim];
    }
}

public class Game
{
    private Mover m;

    public Game()
    {
        m = new Mover();
    }
    /*Methods*/
}

public class Mover
{
    /*Methods*/
}

Answer 2

This sentence

public GameData() { game = new Game(); }

makes no sense; as GameData is the parent, is not logical to have a child inside the parent. Obviously that makes a loop, as you are creating a Game : GameData over and over with that sentence.

Think about inheritance you want, as you are using it incorrectly with Mover too.

Answer 3

Well you definitely have a circular reference which is a design smell. You could stop the infinite loop by checking for null :

public GameData()
{
    if(game == null)
        game = new Game();
}

Or pass the Game instance in to the constructor rather than creating a new one - hard to say what's correct without knowing more of your overall design.