更改使用泛型的抽象类的实例

Question

我试图替换基类中的派生实例.它适用于动物(简单使用抽象类),但不适用于泛型.错误在于SomeMethod.有没有干净的解决方案？

编辑:在另一个界面的帮助下,它是真正可行的.用[S]评论的代码是我原始问题的解决方案.

public abstract class Animal
{
    public void Feed()
    {
    }
}

public class Tiger:Animal
{
}

public class Dog : Animal
{
}

public class Consumer
{
    public Tiger Tiger { get; set; }
    public Dog Dog { get; set; }

    public Animal FavoriteAnimal { get; set; }

    void SomeMethod()
    {
        // This is fine
        FavoriteAnimal = Tiger;
        FavoriteAnimal = Dog;
        FavoriteAnimal.Feed();

        //Also fine 
        int numberOfDogs = PlaceForDogs.CountAnimals();
        int numberOfTigers = PlaceForTigers.CountAnimals();

        //[S] This is doable now
        FavoritePlaceForAnimals = PlaceForDogs;//[S]  no more ERROR
        int numberOfAnimalsOnMyFavoritPlace = FavoritePlaceForAnimals.CountAnimals(); // No error, but I do not get here...
    }

    public PlaceForDogs PlaceForDogs { get; set; } = new PlaceForDogs();
    public PlaceForTigers PlaceForTigers { get; set; } = new PlaceForTigers();

    //public PlaceForAnimals<Animal> FavoritePlaceForAnimals { get; set; }
    //[S] favorite place is of type IPlaceForAnimals instead of PlaceForAnimals
    public IPlaceForAnimals FavoritePlaceForAnimals { get; set; }
}

//[S]new interface
public interface IPlaceForAnimals
{
    int CountAnimals();
}

//[S]abstract class implements the interface
public abstract class PlaceForAnimals<T>:IPlaceForAnimals  where T : Animal
{

    public List<T> Animals { get; set; }

    public int CountAnimals()
    {
        //special counting using properties from Animal class
        return 0;
    }

}

Answer 1

A PlaceForAnimals<Dog>不是PlaceForAnimals<Animal>(为了分配它的类型),因为它不能容纳老虎(原来可以).

没有协方差,这项任务根本就不合法.如果要访问某些方法,可以让基类实现非泛型接口,并使其FavoritePlaceForAnimals成为该类型.