1.定义：
定义一个用于创建对象的接口，让子类决定实例化哪一个类。Factory Method使得一个类的实例化延迟到子类。
2.实现代码如下：
/// <summary>
/// 工厂方法
/// </summary>
public abstract class Factory
{
public abstract Compute GetCompute();
} public class AddFactory : Factory
{
public override Compute GetCompute()
{
return new AddCompute();
}
}
public class JianFaFactory : Factory
{
public override Compute GetCompute()
{
return new SubCompute();
}
}
public class ChengFaFactory : Factory
{
public override Compute GetCompute()
{
return new ChengFaCompute();
}
}
public class ChuFaFactory : Factory
{
public override Compute GetCompute()
{
return new ChuFaCompute();
}
} /// <summary>
/// 计算类
/// </summary>
public abstract class Compute
{
protected int number1; public int Number1
{
get { return number1; }
set { number1 = value; }
}
protected int number2; public int Number2
{
get { return number2; }
set { number2 = value; }
} public abstract int GetResult(); } /// <summary>
/// 加法
/// </summary>
public class AddCompute : Compute
{
public override int GetResult()
{
return number1 + number2;
}
}
/// <summary>
/// 减法
/// </summary>
public class SubCompute : Compute
{
public override int GetResult()
{
return number1 - number2;
}
}
/// <summary>
/// 乘法
/// </summary>
public class ChengFaCompute : Compute
{
public override int GetResult()
{
return number1 * number2;
}
} /// <summary>
/// 除法
/// </summary>
public class ChuFaCompute : Compute
{
public override int GetResult()
{
return number1 / number2;
}
}
static void Main(string[] args)
{
int number1 = ;
int number2 = ; Factory factory = null;
string operate = "+";
switch (operate)
{
case "+":
factory = new AddFactory();
break;
case "-":
factory = new JianFaFactory();
break;
case "*":
factory = new ChengFaFactory();
break;
case "/":
factory = new ChuFaFactory();
break;
default:
break;
}
Compute compute = factory.GetCompute(); compute.Number1 = number1;
compute.Number2 = number2;
Console.WriteLine(compute.GetResult());
Console.ReadKey();
}
3.和简单工厂不同的地方是
(1)简单工厂是由switch直接创建具体的产品对象，而工厂方法是swith延迟创建具体的产品对象，先创建相应的工厂，在延迟创建具体的产品对象
(2)简单工厂只能创建一个工厂，工厂方法可以创建多个工厂
4.工厂方法的好处：
(1)用工厂方法在一个类的内部创建对象通常比直接创建对象更灵活。
(2)Factory Method模式通过面向对象的手法，将所要创建的具体对象的创建工作延迟到了子类，从而提供了一种扩展的策略，较好的解决了这种紧耦合的关系。