我可以使用Decorator模式来包装方法体？ [英] Can I use the decorator pattern to wrap a method body?

问题描述

我有一堆具有不同签名的方法。这些方法有脆弱的数据连接交互，所以我们经常使用一个辅助类来执行重试/重新连接，等等，像这样：

I have a bunch of methods with varying signatures. These methods interact with a fragile data connection, so we often use a helper class to perform retries/reconnects, etc. Like so:

MyHelper.PerformCall( () => { doStuffWithData(parameters...) });

这工作得很好，但它可以使代码有点cluttery。我宁愿做的是装饰与像这样的数据连接的交互方式：

And this works fine, but it can make the code a little cluttery. What I would prefer to do is decorate the methods that interact with the data connection like so:

[InteractsWithData]
protected string doStuffWithData(parameters...)
{
     // do stuff...
}

和则基本上，只要 doStuffWithData 被调用，该方法的机构将被作为一个动作<传递/ code>到 MyHelper.PerformCall（）。我该怎么做呢？

And then essentially, whenever doStuffWithData is called, the body of that method would be passed in as an Action to MyHelper.PerformCall(). How do I do this?

推荐答案

.NET属性是元数据，而不是装饰/自动被调用的活性成分。没有办法实现这种行为。

.NET Attributes are meta-data, not decorators / active components that automatically get invoked. There is not way to achieve this behaviour.

您可以使用属性，通过将装饰码的属性类实现的装饰，并呼吁有一个辅助方法调用方法使用反射在属性类中的方法。但我不知道这将是在只调用直接在装饰法的一大进步。

You could use attributes to implement decorators by putting the decorator code in the Attribute class and call the method with a helper method that invokes the method in the Attribute class using Reflection. But I'm not sure this would be a big improvement over just calling the "decorator-method" directly.

的装饰属性：

[AttributeUsage(AttributeTargets.Method)]
public class MyDecorator : Attribute
{
    public void PerformCall(Action action)
    {
       // invoke action (or not)
    }
}

的方法：的

[MyDecorator]
void MyMethod()
{
}

的用法：的

InvokeWithDecorator(() => MyMethod());

的辅助方法：的

void InvokeWithDecorator(Expression<Func<?>> expression)
{
    // complicated stuff to look up attribute using reflection
}

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看一看的面向方面的编程框架在C＃。这些可以提供你想要的东西。

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Have a look at frameworks for Aspect Oriented Programming in C#. These may offer what you want.

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