2. 类应设计的对扩展开放，对修改关闭。
实例：
<pre name="code" class="csharp"> // 装饰者模式抽象类
public abstract class BaseDecorator
{
protected ReturnInfo returnInfo = new ReturnInfo() { Code = 1, IsSuccess = false };
public BaseDecorator decorator = null;
//装饰者模式必须要传入上一个装饰者对象，如果没有则传null
public BaseDecorator(BaseDecorator _decorator)
{
decorator = _decorator;
}
// 执行方法
public abstract ReturnInfo Run(string orderId,string supplierId,string supOrderId);
// 返回结果
protected ReturnInfo GetResult()
{
returnInfo.Code = 0;
returnInfo.IsSuccess = true;
returnInfo.Message = "操作成功";
return returnInfo;
}
} public class DecoratorA:BaseDecorator
{
public DecoratorA(BaseDecorator decorator)
: base(decorator)
{
}
public override Model.ReturnInfo Run(string orderId, string supplierId, string supOrderId)
{
//具体执行的方法
//判断是否还有装饰者需要执行
if (decorator!=null)
{
return decorator.Run(orderId, supplierId,supOrderId);
}
else
{
return GetResult();
}
}
} public class DecoratorB:BaseDecorator
{
public DecoratorB(BaseDecorator decorator)
: base(decorator)
{
}
public override Model.ReturnInfo Run(string orderId, string supplierId, string supOrderId)
{
//具体执行的方法
//判断是否还有装饰者需要执行
if (decorator!=null)
{
return decorator.Run(orderId, supplierId,supOrderId);
}
else
{
return GetResult();
}
}
}public class Test
{
BaseDecorator decorator = new DecoratorA(null);
decorator = new DecoratorB(decorator);
//程序是从下往上执行的
return decorator.Run(orderId,supplierId,supOrderId);
}
原文：http://blog.csdn.net/zzr494684778/article/details/39671399