CODEWITHSUNDEEP
c#genericsinheritanceoverridingspecialization
Gavyn
Gavyn

Reputation: 56

How to override in a child class a method of a base class which does not know the type of a parameter but only the child?

Assuming that doing typecasting isn't viable for performance reasons:

public class ai_task
{
    public virtual TaskStatus StartTask(Base_NPC mRef) { return TaskStatus.STARTED; }
    public virtual TaskStatus RunTask(Base_NPC mRef) { return TaskStatus.RUNNING; }
    public virtual void EndTask(Base_NPC mRef) { }
}

Say we have this base class for all NPCs and we want to get around to making different tasks for different types of NPCs.

This is what I have:

public class Shoot_Target : ai_task
{
    public TaskStatus StartTask(Shooter_NPC mRef)
    {
        //Shoot target, pew pew
        return base.StartTask(mRef);
    }
}

Is this the best way to go about handling it?

And if not, what is the best approach?

Keep in mind the functions are virtual in ai_task because I may want to create generic tasks that can be applied to all NPCs.

Upvotes: 1

Views: 398

Answers (1)

Gavyn
Gavyn

Reputation: 56

Turns out generics were the answer.

Here is a test snippet that I put in another program:

//Parent class
public class Animal
{
  public virtual void Speak()
  {
    Console.WriteLine("I'm an animal, I don't speak");
  }
}

//Child class
public class Human : Animal
{
  public override void Speak()
  {
    Console.WriteLine("I'm a more evolved animal. I DO speak.");
  }

  public void InventStuff()
  {
    Console.WriteLine("And also as a human I can do things like invent tools.");
  }
}

public enum TaskStatus
{
  STARTED = 0,
  RUNNING,
  COMPLETE,
  FAIL
}

public class ai_task<T>
{
  public virtual TaskStatus StartTask(T mRef) { return TaskStatus.STARTED; }
}

public class Speak_Task : ai_task<Animal>
{
  public override TaskStatus StartTask(Animal mRef)
  {
    mRef.Speak();
    return base.StartTask(mRef);
  }
}

public class Invent_Task : ai_task<Human>
{
  public override TaskStatus StartTask(Human mRef)
  {
    mRef.InventStuff();
    return base.StartTask(mRef);
  }
}

Below snippet for output:

var man = new Human();
var dog = new Animal();
var spktask = new Speak_Task();
var invtask = new Invent_Task();

Console.WriteLine(spktask.StartTask(man));
Console.WriteLine(spktask.StartTask(dog));
Console.WriteLine(invtask.StartTask(man));

Upvotes: 1

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