Question

我有一些C＃代码，如下所示，我想在添加后删除装饰对象，例如我有一个加牛奶和糖以及饼干的茶，我想从Order类中去除糖，如何使用装饰设计模式：

public abstract class Order
{
    private int _Cost = 0;
    private string _Description = "";
    public virtual int GetCost()
    {
        return _Cost;
    }
    public virtual string GetDescription()
    {
        return _Description;
    }
}

public class Coffee : Order
{
    int _Cost = 3000;
    string _Description = "Coffee";
    public override int GetCost()
    {
        return _Cost;
    }
    public override string GetDescription()
    {
        return _Description;
    }
}

public class Tea : Order
{
    int _Cost = 2000;
    string _Description = "Tea";
    public override int GetCost()
    {
        return _Cost;
    }
    public override string GetDescription()
    {
        return _Description;
    }
}

public abstract class Options : Order
{
    int _Cost = 0;
    string _Description = "No Option";
    public override int GetCost()
    {
        return _Cost;
    }
    public override string GetDescription()
    {
        return _Description;
    }
}

public class Honey : Order
{
    int _Cost = 800;
    string _Description = "Honey";
    public Honey(Order order)
    {
        _Cost = _Cost + order.GetCost();
        _Description = order.GetDescription() + " And " + _Description;
    }
    public override int GetCost()
    {
        return _Cost;
    }
    public override string GetDescription()
    {
        return _Description;
    }
}

public class Biscuit : Order
{
    int _Cost = 400;
    string _Description = "Biscuit";
    public Biscuit(Order order)
    {
        _Cost = _Cost + order.GetCost();
        _Description = order.GetDescription() + " And " + _Description;
    }
    public override int GetCost()
    {
        return _Cost;
    }
    public override string GetDescription()
    {
        return _Description;
    }
}

public class Sugar : Order
{
    int _Cost = 300;
    string _Description = "Sugar";
    public Sugar(Order order)
    {
        _Cost = _Cost + order.GetCost();
        _Description = order.GetDescription() + " And " + _Description;
    }
    public override int GetCost()
    {
        return _Cost;
    }
    public override string GetDescription()
    {
        return _Description;
    }
}

public class Milk : Order
{
    int _Cost = 600;
    string _Description = "Milk";
    public Milk(Order order)
    {
        _Cost = _Cost + order.GetCost();
        _Description = order.GetDescription() + " And " + _Description;
    }
    public override int GetCost()
    {
        return _Cost;
    }
    public override string GetDescription()
    {
        return _Description;
    }
}

如果你尽快回答我，我感激不尽......

Answer 1

你不能也不应该。装饰者的目的是对他们的客户（包括其他装饰者）完全透明。其意图的装饰者也应该用于（由GoF指定）：

动态附加对象的其他职责。

顺便说一下，我认为你的Biscuit或Tea不应该是订单的装饰者（并被视为订单）。创建包含项目列表的Order。即使用聚合而不是继承。考虑服务员创造的订单：

含糖和柠檬的茶x 2
咖啡加牛奶
饼干

我认为您的域名模型应该看起来一样。

在装饰设计模式中删除装饰对象的一些选项

1 个答案: