使用linq过滤可观察的集合

Question

I have an animal class. A herbivore class which inherits from animal and an elephant class which inherits from herbivore . I also have a carnivore class which inherits from animal and a tiger class which inherits from carnivore . I Have a observable collection called zoo with tigers and elephants. I Want to select the Herbivores in the zoo collection. I Then want to add the herbivores to a new observable collection called herb.

var herbivores = from Animal in zoo
                 where Animal == Animal.OfType<Herbivore>()
                 select Animal;

foreach (var item in herbivores)
{
    herb.Add(item);
}                        

Answer 1

You can't use OfType like that; it's an extension method on an enumerable collection, not on the class animal . Do this instead:

var herbivores = zoo.OfType<Herbivore>();

Alternatively you could achieve the same effect with

var herbivores = zoo.Where(a => a is Herbivore);

but there really is no point in doing this the funky way.