public void Contains02()
{
Fruit[] fruits = { new Fruit {
Name = "apple", Code = 9
},
new Fruit {
Name = "orange", Code = 4
},
new Fruit {
Name = "lemon", Code = 12
} };
Fruit apple = new Fruit {
Name = "apple", Code = 9
};
Fruit kiwi = new Fruit {
Name = "kiwi", Code = 8
};
FruitComparer prodc = new FruitComparer();
bool hasApple = fruits.Contains(apple, prodc);
bool hasKiwi = fruits.Contains(kiwi, prodc);
Debug.WriteLine("Apple? " + hasApple);
Debug.WriteLine("Kiwi? " + hasKiwi);
}
static void Main()
{
// Allowed in C# 4.0
ICompareThings <Fruit> fc = new FruitComparer();
Apple apple1 = new Apple();
Apple apple2 = new Apple();
Orange orange = new Orange();
// A fruit comparer can compare apples and oranges:
bool b1 = fc.FirstIsBetter(apple1, orange);
// or apples and apples:
bool b2 = fc.FirstIsBetter(apple1, apple2);
// This is legal because the interface is
// contravariant.
ICompareThings <Apple> ac = fc;
// This is really a fruit comparer, so it can
// still compare two apples
bool b3 = ac.FirstIsBetter(apple1, apple2);
}