C#构造方法(构造函数)

public class Product
    {
        public int ID { get; set; }
        public String NAME { get; set; }
        public Decimal Price { get; set; }
        public ProductType type { get; set; }
        public DateTime Birthday { get; set; }

        public Product()  //无参
        {
            ID = 1100;
            NAME = "手机";
            Price = 8888;
            type = ProductType.手机;
            Birthday = new DateTime(2019, 11, 1);
        }
    }

        public Product()  //无参
        {
            ID = 1100;
            NAME = "手机";
            Price = 8888;
            type = ProductType.手机;
            Birthday = new DateTime(2019, 11, 1);
        }

        public Product(int id,string Name,int price, ProductType type)
        {
            this.ID = id;
            this.NAME = Name;
            this.Price = price;  //this当前对象
        }

            Product s1 = new Product();//无参
            Product s2 = new Product("2000","huawie", 5000,ProductType.服装, new DateTime(2019,2,3)); //有参
            Console.WriteLine(s2.ID+s2.NAME+s2.Price+ProductType.服装);
            Console.ReadLine();
            Console.WriteLine(s1.ID);