Question

Let’s say I’ve got an abstract class called Player. Classes GameAPlayer and GameBPlayer inherit from Player. In turn, a couple of abstract classes inherit from GameAPlayer and GameBPlayer respectively.

Let’s say I’ve got another abstract class called Engine which hosts List<Player>. Classes GameAEngine and GameBEngine both inherit from Engine. I know for a fact that all players in GameAEngine will be of type GameAPlayer, and that all players in GameBEngine will be of type GameBPlayer.

I cannot move List<Player> into GameAEngine and GameBEngine as I’m using the list in Engine itself.

Having to typecast Player into GameAPlayer and GameBPlayer every time I use the list in their respective engines just seems unclean. Is there any way I can avoid having to do this?

Answer 1

Change Engine to Engine<TPlayer> where TPlayer : Player.
Note that this will make base engines require generic type parameters everywhere; you can work around that using a non-generic interface.

Alternatively, make a GetPlayer method in the derived classes that does the cast, and use that instead of the base list.