Question

I´m making this game but I´ve run into a problem with the structures. I´ve made a class called Structure and other classes like Traps, Shelter, Fireplace inherits from this class. The tiles in the game have their own class(Tile) and have a list of Structures on that tile. I can succesfully build structures on tiles which are included in the list. The problem comes when I try to acces the functions from classes like Traps etc. it won´t work. I can only use the functions from the base class Structure.

List in Tile:

class Tile
{
     public List<Structure> Structures = new List<Structure>();
}

How I build a Trap or other building:

        bool anyFireplace = Bundle.map.tile[Bundle.player.X, Bundle.player.Y].Structures.OfType<Shelter>().Any();
        if (!anyFireplace)
        {
            woodlogsCost = 4;
            if (Bundle.player.Woodlogs - woodlogsCost >= 0)
            {
                Bundle.map.tile[Bundle.player.X, Bundle.player.Y].Structures.Add(new Shelter(Bundle.player.X, Bundle.player.Y));
                Bundle.player.Woodlogs -= woodlogsCost;
            }
        }

When I draw the Structures (here is where my problem is, note the comments)

foreach (Structure s in Bundle.map.tile[x, y].Structures)
{
   if (s is Fireplace)
{
   //This is the function from base class Strucure
   s.ColorBody(g, 10, x - minx, y - miny, 0, Brushes.Firebrick);

   // The function that I wan´t to use but can´t be used
   //s.ColorBody(g, x - minx, y - miny); 
}
if (s is Shelter)
{
s.ColorBody(g, 10, x - minx, y - miny, 1, Brushes.ForestGreen);
}
if (s is Sleepingplace)
{
   s.ColorBody(g, 10, x - minx, y - miny, 2, Brushes.Brown);
}
if (s is Trap)
{
   s.ColorBody(g, 10, x - minx, y - miny, 3, Brushes.Silver);
}
if (s is Barricade)
{
   s.ColorBody(g, 10, x - minx, y - miny, 4, Brushes.DarkOliveGreen);
}
}

Soo… I wonder how do I access the functions I wan´t to use?

Answer 1

To the computer, s is only a Structure. If you want to call a specific method that only the Fireplace class has but the abstract class Structure does not have (e.g. Fireplace class might have a BurnWood() method that wouldn’t make sense for a Structure to have), then you want to let the computer know that this Structure is actually also a Fireplace (for example). So you could do this by casting; for example:

((Fireplace)s).ColorBody(g, x - minx, y - miny); 

or

(s as Fireplace).ColorBody(g, x - minx, y - miny); 

See this post on the difference between casting and using the as operator.