Code
NYPizzaFactory nyFactory = new NYPizzaFactory(); // 创建具有纽约风味的Pizza工厂
PizzaStore nyStore = new PizzaStore(nyFactory);  // 建立Pizza店，经营纽约风味的Pizza
nyStore.OrderPizza("cheese");                    // 订购具有纽约风味的CheesePizza
.其它具体工厂

Code
class Program
    {
        static void Main(string[] args)
        {
            PizzaStore nyStore = new NYPizzaStore();
            PizzaStore chicagoStore = new ChicagoPizzaStore();

            Pizza pizza = nyStore.OrderPizza("cheese");
            Console.WriteLine("Ethan ordered a " + pizza.GetName());

            pizza = chicagoStore.OrderPizza("cheese");
            Console.WriteLine("Joel orderd a " + pizza.GetName());

            Console.ReadLine();
        }
    }
public class NYPizzaStore : PizzaStore
    {        
        public override Pizza CreatePizza(String paramPizzaType)
        {
            Pizza pizza = null;
            if (paramPizzaType.Equals("cheese"))
            {
                pizza = new NYStyleCheesePizza();
            }
            else if (paramPizzaType.Equals("greek"))
            {
                pizza = new NYStyleGreekPizza();
            }
            else if (paramPizzaType.Equals("pepperon"))
            {
                pizza = new NYStylePepperoniPizza();
            }
            return pizza;
        }
    }
public class ChicagoPizzaStore : PizzaStore
    {
        public override Pizza CreatePizza(String paramPizzaType)
        {
            Pizza pizza = null;
            if (paramPizzaType.Equals("cheese"))
            {
                pizza = new ChicagoStyleCheesePizza();
            }
            else if (paramPizzaType.Equals("greek"))
            {
                pizza = new ChicagoStyleGreekPizza();
            }
            else if (paramPizzaType.Equals("pepperon"))
            {
                pizza = new ChicagoStylePepperoniPizza();
            }
            return pizza;
        }
    }
public abstract class PizzaStore
    {
        public abstract Pizza CreatePizza(String paramType);        

        public Pizza OrderPizza(String paramType)
        {
            Pizza pizza = CreatePizza(paramType);
            pizza.Prepare();
            pizza.Bake();
            pizza.Cut();
            pizza.Box();
            return pizza;
        }
    }
public abstract class Pizza
    {
        protected string name;    // 名称
        protected string sauce;   // 酱料类型
        protected string daugh;   // 面团类型
        protected List<string> toppings = new List<string>();  // 一套佐料

        public void Prepare()
        {
            Console.WriteLine("Preparing " + name);
            Console.WriteLine("Tossing dough  ");
            Console.WriteLine("Adding sauce ");
            Console.WriteLine("Adding toppings : ");
            foreach (string str in toppings)
            {
                Console.WriteLine("  " + str);
            }
        }

        public virtual void Bake()
        {
            Console.WriteLine("Bake for 25 minutes at 350 ");
        }

        public virtual void Cut()
        {
            Console.WriteLine("Cutting the pizza into diagonal slices ");
        }

        public virtual void Box()
        {
            Console.WriteLine("Place pizza in official PizzaStore box");
        }

        public String GetName()
        {
            return name;
        }
    }
public class ChicagoStyleCheesePizza :Pizza
    {
        public ChicagoStyleCheesePizza()
        {
            name = "Chicago Style Deep Dish Cheese Pizza";
            daugh = "Extra Thick Crust Dough";
            sauce = "Plum Tomato Sauce ";

            toppings.Add("Shredded Mizzarella Cheese ");
        }

        public override void Cut()
        {
            Console.WriteLine("Cutting the pizza into squre slices "); // 芝加哥的Pizza切成方形
        }
    }
public class NYStyleCheesePizza:Pizza
    {
        public NYStyleCheesePizza()
        {
            name = "NY Style Sauce and Cheese Pizza";
            daugh = "Thin Crust Dough";
            sauce = "Marinara Sauce ";

            toppings.Add("Grated Regggiano Cheese");
        }
    }