Question

我知道如何用Java做到这一点，但是C＃无法正常工作。我确定我缺少明显的东西。如您所见，如果宠物不是狗，我想将宠物降为狗。我认为垂头丧气是对的，但也许并非如此。问题是此行Console.WriteLine("{0,12}\t {1}\t {2,10:C}\t {3}\t {4}", Name, Type, Price, Weight, Sound(), AKCRegistration);不允许我访问我所指的吸气剂。

这是我的主班

        static void Main(string[] args)
        {
            Pet[] pets = new Pet[5];
            pets[0] = new Dog("King", 55, PET_TYPE.Canine, "akc1000", 1000);
            pets[1] = new Dog("Princess", 25, PET_TYPE.Canine, "akc1000", 2000);
            pets[2] = new Dog("Spike", 25, PET_TYPE.Canine, "akc1000", 25);
            pets[3] = new Cat("Missy", 15, PET_TYPE.Feline, 50);
            pets[4] = new Cat("Mr Boogangle", 5, PET_TYPE.Feline, 30);

            //for (int i = 0; i < pets.Length; i++)
            //{
            //    Console.WriteLine($"{pets[i]}");
            //}

            for each (Pet pet in pets)
            {
                if (pet is Dog)
                {
                    Dog Pet = (Dog) pet;

                    Console.WriteLine("{0,12}\t {1}\t {2,10:C}\t {3}\t {4}", Name, Type, Price, Weight, Sound(), AKCRegistration);
                }
            }

这是我的Dog课程

class Dog: Pet
    {
        private string aKCregistration;

        public Dog(string name, int weight, PET_TYPE type, string AKC, double price) : base(name, weight, type, price)
        {
            this.aKCRegistration = AKC;
            if (aKCRegistration == "")
            {
                aKCRegistration = "Mutt";
            }
        }

        public int AKCRegistration { get; set; }

        public override string Sound()
        {
            return "Woof, Woof";
        }

        public override string ToString()
        {
            return String.Format("{0,12}\t {1}\t {2,10:C}\t {3}\t {4}", Name, Type, Price, Weight, Sound());
        }
    }

我的宠物班

public enum PET_TYPE
    {
        Canine, Feline
    }

    public abstract class Pet
    {
        internal string name;
        internal int weight;
        internal PET_TYPE type;
        internal double price;

        public Pet(string name, int weight, PET_TYPE type, double price)
        {
            this.name = name;
            this.weight = weight;
            this.type = type;
            this.price = price;
        }

        public string Name
        {
            get { return name; }
            set { name = value; }
        }

        public int Weight
        {
            get { return weight; }
            set { weight = value; }
        }

        public double Price
        {
            get { return price; }
            set { price = value; }
        }

        public PET_TYPE Type
        {
            get { return type; }
            set { type = value; }
        }

        public override string ToString()
        {
            return String.Format("{0,12}\t {1}\t {2,10:C}\t {3}\t {4}", Name, Type, Price, Weight, Sound());
        }

        public abstract string Sound();


    } // end class pet

除了猫类，我包括了所有东西，如果您需要看的话，请告诉我。

Answer 1

在这种情况下，您不使用实例变量Pet来引用它们，因为您是从类外部访问它们的，因此需要在它们上指定实例变量以告知您正在访问哪个对象的状态喜欢：

Console.WriteLine("{0,12}\t {1}\t {2,10:C}\t {3}\t {4}", 
                   Pet.Name, 
                   Pet.Type, 
                   Pet.Price, 
                   Pet.Weight, 
                   Pet.Sound(), 
                   Pet.AKCRegistration);

并且您正在覆盖ToString中的Dog成员函数时，您也可以这样称呼它：

string petString = Pet.ToString();

当您访问类Dog中的对象时，这意味着您正在引用当前调用ToString方法的对象，因此该方法无需显式指定任何实例即可工作，您可以认为像这样的

Console.WriteLine("{0,12}\t {1}\t {2,10:C}\t {3}\t {4}", 
                   this.Name, 
                   this.Type, 
                   this.Price, 
                   this.Weight, 
                   this.Sound(), 
                   this.AKCRegistration);

但是我们不需要显式添加this，因为编译器会解决这个问题。

我如何访问从单独的类到主类的getter和setter（在C＃中向下转换）

1 个答案: