C# 重写IComparer以使用lambda表达式

我正试图重写我的IComparer以使用lambda表达式，但我似乎无法正确完成此操作

public class AnimalCarriageSorter : IComparer<Animal>
{
    public int Compare(Animal animal, Animal targetAnimal)
    {
        //Compare diet first.
        if (animal.FoodDiet.CompareTo(targetAnimal.FoodDiet) != 0) 
        {
            return animal.FoodDiet.CompareTo(targetAnimal.FoodDiet);
        }

        //Compare size.
        return targetAnimal.Size.CompareTo(animal.Size);
    }
}

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问题是您已将比较从animal.CompareTargetAnimal切换到targetAnimal.CompareTAnimal，因此无法获得一致的结果。在这两种情况下，您都应该将动物作为第一个对象

例如：

public int Compare(Animal animal, Animal targetAnimal)
{
    // Compare diet first.
    if (animal.FoodDiet.CompareTo(targetAnimal.FoodDiet) != 0)
    {
        return animal.FoodDiet.CompareTo(targetAnimal.FoodDiet);
    }

    // Compare size.
    return animal.Size.CompareTo(targetAnimal.Size);
}

或者你可以简化一点：

public int Compare(Animal animal, Animal targetAnimal)
{
    return animal.FoodDiet.CompareTo(targetAnimal.FoodDiet) != 0 
        ? animal.FoodDiet.CompareTo(targetAnimal.FoodDiet) 
        : animal.Size.CompareTo(targetAnimal.Size);
}

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您可以使用Func而不是IComparer轻松地重写它，例如

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请详细说明您希望比较器如何准确工作。lambda表达式在哪里？什么是你不能正确完成的？

Func<Animal, Animal, int> comparer = (x, y) => 
    x.FoodDiet.CompareTo(y.FoodDiet) != 0 ? 
        x.FoodDiet.CompareTo(y.FoodDiet) : 
        x.Size.CompareTo(y.Size)