一、简单工厂模式

@#

public class Operation  //基类
    {private double _numberA = 0;private double _numberB = 0;public double NumberA{get{ return _numberA; }set{_numberA = value;}}public double NumberB{get{ return _numberB; }set{_numberB = value;}}public virtual double GetResult(){double result = 0;return result;}}

##

    class OperationAdd:Operation    //加法类
    {public override double GetResult(){double result = 0;result = NumberA + NumberB;return result;}}class OperationSub:Operation    //减法类
    {public override double GetResult(){double result = 0;result = NumberA - NumberB;return result;}}

##

public class OperationFactory   //工厂类
    {public static Operation CreateOperate(string operate){Operation oper = null;switch(operate){case "+":oper = new OperationAdd();break;case "-":oper = new OperationSub();break;                  }return oper;}}

##

    class Program   //前台代码
    {static void Main(string[] args) {Operation oper = OperationFactory.CreateOperate("+");oper.NumberA = 20;oper.NumberB = 80;double result = oper.GetResult();Console.WriteLine(result);}}