Question

For my game, I’m making a resource class which manager resources likes textures, sounds, fonts, etc. I made this ImageList class, which automatically loads textures during runtime as they’re needed.

class TextureList
{
    private Dictionary<string, Texture> _list;

    public Texture this[string name]
    {
        get
        {
            Texture tex;
            bool success = List.TryGetValue(name, out tex);

            if (!success)
            {
                tex = Resources.LoadImage(name);
                List[name] = tex;
            }

            return tex;
        }
    }

    protected Dictionary<String, Texture> List
    {
        get
        {
            return _list ?? new Dictionary<String, Texture>();
        }
    }
}

Now I want to make to make this class generic, so that I can make a FontList or SoundList class without the hassle of changing every Texture to Sound or Font (and writing lots of duplicate code). Anyone willing to help me out on making a generic version of this?

Answer 1

1. Make your class generic
2. In the constructor, you must pass a Func where T is your generic argument.
3. The logic goes: When you do not find the item, the passed in Func is called and the result stored in the internal list.

so, your class becomes

var x = new Cachinglist<Texture>(s => Resources.LoadImage(s));

or

class CachingList<T>
{
    private readonly Dictionary<string, T> _list = new Blabla..();
    private readonly Func<string,T> _itemsFactory;

    public CachingList(Func<string,T> itemsFactory) {
      _itemsFactory = itemsFactory;
    }

    public T this[string name]
    {
        get
        {
            T t;

            if (!_list.TryGetValue(name, out t))
            {
                t = _itemsFactory(name);
                _list[name] = t;
            }

            return t;
        }
    }
}