Overriding Abstract Method C# for different child abstract classes

Question

public abstract class Problem
{
    public abstract List<Action> GetPossibleActions(State currentState);
}

Here both Action and State classes are also Abstract Classes.

In the child class of Problem, I am implementing that abstract method with using children of Action and State. Now it gives me error because I didnt use the same Abstract classes for return type and argument.

public class PizzaProblem : Problem
{
    public List<PizzaAction> GetPossibleActions(PizzaState currentState)
    {
       ......
    }

}

Answer 1

You could make your class a generic class:

public abstract class Problem<TAction, TState>
  where TAction : Action
  where TState : State
{
    public abstract IList<TAction> GetPossibleActions(TState currentState);
}

public class PizzaProblem : Problem<PizzaAction, PizzaState> { ...

Or don't care about the concrete type contained in your list: rely on polymorphism to call the correct methods.

Answer 2

The signature needs to stay the same way as in the abstract class. Try

public List<Action> GetPossibleActions(State currentState)
{
    // Your code
}

Also Action is an object for it self. If you didn't define the PizzaAction type which inherits from action, it won't work. Same is valid for State.