Question

This may be the wrong title for what I am looking for, but I think it boils down to a class factory.

I have three classes:

   class Horse : Animal
   class Cow :   Animal

What I want to create is a method in Animal that, pseudocoded, would work like this:

   List<Horse or Cow> (Animal horseOrCow)
   {
      if (horseOrCow is of type Horse)
         return a list of 10 Horse objects; 
      else
         return a list of 10 Cow objects;
   }

A simplification of course, but once I grasp how to do this, I should be able to figure out the rest.

(Edit: Typo fixed).

Answer 1

You can use the is-operator and Enumerable.OfType + Enumerable.Take:

public List<Animal> getMammals(Mammal horseOrCow)
{
    if (horseOrCow is Horse)
        return allAnimals.OfType<Horse>().Take(10).Cast<Animal>().ToList();
    else if (horseOrCow is Cow)
        return allAnimals.OfType<Cow>().Take(10).Cast<Animal>().ToList();
    else
        throw new ArgumentException("Invalid Mammal", "horseOrCow");
}

assuming that there is a List<Animal> allAnimalssomewhere.

Edit: Mammal must also be an Animal and since Horse and Cow are Mammals they should inherit from it.

class Horse : Mammal{ }
class Cow : Mammal { }
class Animal { }
class Mammal : Animal { }