public static void Run()
{
// Contravariance - permits use a method with less derived types in argument for a delegate.
// delegate requires Animal and method requires Animal
FeedAnimal feedAnimalWater = DrinkWater;
feedAnimalWater(new Animal());
feedAnimalWater(new Cat());
// delegate requires Animal + method requires Cat
// It is not possible to pass any animal if we expect only cats.
//FeedAnimal feedAnimalMilk = DrinkMilk;
// delegate requires Cat and method requires Animal
// It is possible because of Contravariance - A cat can drink water.
FeedCat feedCatWater = DrinkWater;
feedCatWater(new Cat());
// delegate requires Cat and method requires Cat
FeedCat feedCatMilk = DrinkMilk;
feedCatMilk(new Cat());
}
private void Btn_feedAnimal_Click(object sender, EventArgs e)
{
Animal foundAnimal = new Animal();
if ((foundAnimal = FindAnimal(SaveAnimalName)) != null)
{
FeedAnimal feedAnimal = new FeedAnimal(foundAnimal, ListOfAnimals);
saveFedFoodAmount = feedAnimal.FoodAmount;
var result = feedAnimal.ShowDialog();
}
else
{
MessageBox.Show("Tier wurde nicht gefunden.", "", MessageBoxButtons.OK);
}
}
