C#委托 模板和回调函数

资料源于刘铁猛的C#视频教程

模板方法

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Del
{
    public delegate double Calc(double x, double y);//委托是类申明时与类平级

    class Program
    {
        static void Main(string[] args)
        {
            ProductFactory proFac = new ProductFactory();
            WrapFactory wrapFac = new WrapFactory();

            Func<Product> func1 = new Func<Product>(proFac.MakePizza);
            Func<Product> func2 = new Func<Product>(proFac.MakeToyCar);

            Box box1 = wrapFac.WrapProduct(func1);
            Box box2 = wrapFac.WrapProduct(func2);
            Console.WriteLine(box1.Product.Name);
            Console.WriteLine(box2.Product.Name);

        }
    }
    class Logger
    {
        public   void Log(Product product)
        {
            Console.WriteLine("Product {0} created at {1}. Price is {2}. ", product.Name, DateTime.UtcNow, product.Price);
        }
    }
    class Product
    {
        public string Name { get; set; }
        public double Price { get; set; }

    }

    class Box
    {
        public Product Product { get; set; }
    }

    class WrapFactory
    {
        public Box WrapProduct(Func<Product> getProduct)//函数模板
        {
            Box box = new Box();
            Product product = getProduct.Invoke();
            box.Product = product;
            return box;
        }
    }

    class ProductFactory
    {
        public Product MakePizza()
        {
            Product product = new Product();
            product.Name = "Pizza";
            return product;
        }

        public Product MakeToyCar()
        {
            Product product = new Product();
            product.Name = "Toy Car";
            return product;
        }
    }
}

回调方法

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Del
{
    public delegate double Calc(double x, double y);//委托是类申明时与类平级

    class Program
    {
        static void Main(string[] args)
        {
            ProductFactory proFac = new ProductFactory();
            WrapFactory wrapFac = new WrapFactory();

            Func<Product> func1 = new Func<Product>(proFac.MakePizza);
            Func<Product> func2 = new Func<Product>(proFac.MakeToyCar);

            Logger logger = new Logger();
            Action<Product> log = new Action<Product>(logger.Log);


            Box box1 = wrapFac.WrapProduct(func1, log);
            Box box2 = wrapFac.WrapProduct(func2, log);
            Console.WriteLine(box1.Product.Name);
            Console.WriteLine(box2.Product.Name);


        }
    }
    class Logger
    {
        public   void Log(Product product)
        {
            Console.WriteLine("Product {0} created at {1}. Price is {2}. ", product.Name, DateTime.UtcNow, product.Price);
        }
    }
    class Product
    {
        public string Name { get; set; }
        public double Price { get; set; }

    }

    class Box
    {
        public Product Product { get; set; }
    }

    class WrapFactory
    {
        //没有返回值的用action委托
        public Box WrapProduct(Func<Product> getProduct, Action<Product> logCallback)
        {
            Box box = new Box();
            Product product = getProduct.Invoke();
            if (product.Price >= 50)
            {
                logCallback(product);
            }

            box.Product = product;
            return box;
        }
    }

    class ProductFactory
    {
        public Product MakePizza()
        {
            Product product = new Product();
            product.Name = "Pizza";
            product.Price = 15;
            return product;
        }

        public Product MakeToyCar()
        {
            Product product = new Product();
            product.Name = "Toy Car";
            product.Price = 150;
            return product;
        }
    }
}