链式编程学习之练习篇

classProgram
    {
        //study chained call 链式调用
        static void Main(string[] args)
        {
            //One 
            //Product p = new Product() { ProductName = "iphone5", Price = 300 }.First().Sencond().Third();
            //Two

            List<Product> list = new List<Product>()
            {
                new Product{ProductName="iphone5",Price=300},
                new Product{ProductName="iphone4s",Price=200},
                new Product{ProductName="ipad4",Price=100}
            };
            var s = list.GetIphone<Product, Product>(p =>
            {
                if (p.ProductName.Contains("iphone"))
                {
                    returnp;
                }
                else
                    return null;
            }).getFirst<Product>();
            Console.WriteLine(s.Price);
            Console.ReadKey();
        }
    }
    public classProduct
    {
        public string ProductName { get; set; }
        public int Price { get; set; }
        publicProduct First()
        {
            Console.WriteLine("First");
            return this;
        }
        publicProduct Sencond()
        {
            Console.WriteLine("Second");
            return this;
        }
        publicProduct Third()
        {
            Console.WriteLine("Third");
            return this;
        }
    }
    static classProductExtension
    {
        //get iphone
        public static IEnumerable<TResult> GetIphone<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult>selector)
        {
            foreach (var t insource)
            {
                if (selector(t) != null)
                {
                    yield returnselector(t);
                }
            }
        }
        //get first
        public static Tsource getFirst<Tsource>(this IEnumerable<Tsource>ilist)
        {
            returnilist.First();
        }
    }