How to call property from inherited class per base class?

Question

I don't really know if it's even possible, but it would be nice if it would. So, for my Role-Playing-Game, I tried to implement some other possible Quest-schemes (until know there were only the possibility of a monster-hunting-quest, now I wanted to implement some kinds of "Talk to this person"-Quests or "Find that and that Item"-Quest). So I created a new Quest-Class, renamed the old Quest-Class to MonsterQuest and inherited it from Quest. So now, I have a List and want to go trough all elements until I find one element with KilledMonsters higher than 3, for example. THE PROBLEM is, that KilledMonster isn't implemented in the base-class, but only in the MonsterQuest-Class :(

Here are the classes how they are right now:

Quest

public class Quest
{
    public int Accept_MinLevel { get; protected set; }
    public string NPC_Name { get; protected set; }
    public bool Accepted { get; protected set; }
    public bool Completed { get; set; }
    public bool HasStillRewards = true;

    public double Reward_Experience { get; protected set; }
    public int Reward_Money { get; protected set; }

    public Quest(int accept_MinLevel, string npc_Name, double reward_experience, int reward_Money)
    {
        Accept_MinLevel = accept_MinLevel;
        NPC_Name = npc_Name;
        Reward_Money = reward_Money;
        Reward_Experience = reward_experience;
    }

    public virtual void Update(GameTime gameTime)
    {
    }

    public bool WaitForReward()
    {
        return Completed && HasStillRewards;
    }
}

MonsterQuest

public class MonsterQuest : Quest
{
    public List<Enemy> KilledEnemyList = new List<Enemy>();

    public int RequiredMonster_Amount { get; private set; }
    public string RequiredMonster_Name { get; private set; }
    public int RequiredMonster_MinLevel { get; private set; }

    public MonsterQuest(string npcName, int accept_MinLevel, string requiredMonster_Name, int requiredMonster_MinLevel, int requiredMonster_Amount, double reward_Experience, int reward_Money) : base(accept_MinLevel, npcName, reward_Experience, reward_Money)
    {
        NPC_Name = npcName;
        Accept_MinLevel = accept_MinLevel;
        RequiredMonster_Amount = requiredMonster_Amount;
        RequiredMonster_MinLevel = requiredMonster_MinLevel;
        RequiredMonster_Name = requiredMonster_Name;
        Reward_Experience = reward_Experience;
        Reward_Money = reward_Money;
    }

    public override void Update(GameTime gameTime)
    {
        if (KilledEnemyList.Capacity >= RequiredMonster_Amount)
            Completed = true;
    }
}

and, how I said, I want to do that (from another class. QuestList is just a List where I added a MonsterQuest element. This snippet is a part of my Enemy-Class, just to notice^^)

foreach (var item in Storyline.QuestList.Where(c => c.Accepted && !c.Completed && c.RequiredMonster_Name == Name && c.RequiredMonster_MinLevel <= Level))
            {
                item.KilledEnemyList.Add(this);
            }

I hope anyone understand my problem and can help me solve it :) Have a nice evening

Answer 1

Probably the best way to summarize this is that a base class knows nothing about the class(es) that may or may not be inheriting it. The best it can do is to define certain signatures that any inheriting class must implement.

In general, there are a few ways to deal with this. One way is to make the base class abstract, define its functionality, and a set of abstract signatures that each deriving class must meet. In which case, you would always make calls to the children class - but could still have common code reuse in the base class.

Another approach is to create an interface, say IKillable, then have classes all implement them. Then you can make a call against an IKillable object.

Looking for some good tutorials on abstract classes and interfaces will get you what you need I suspect.

Hope that gets you started.