工厂方法

以计算器为例:

public class Operation

{

　　public double numbera;

　　public double numberb;

　　public virtual double getresult()

　　{

　　　　return 0;

　　}

}

//加法

public class OperationAdd : Operation

{

　　public overidde double getresult()

　　{

　　　　return numbera + numberb;

　　}

}



//创建操作工厂内

public interface IFactory

{

　　Operation CreateOperation();

}



//加法工厂

public class FactoryAdd : IFactory

{

　　public Operation CreateOperation()

　　{

　　　　return new OperationAdd();

　　}

}

//使用

public class Program
{
    public static void Main()
    {
       IFactory fac= new FactoryAdd();
       Operation op = fac.CreateOperation();
       op.numbera = 1;
       op.numberb = 2;
     　Console.WriteLine(op.getresult());
     }          
}