如何在运行时扩展方法? [英] How to extend a method at runtime?
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问题描述
这是课程:
class Foo
{
private void Boo()
{
// Body...
}
// Other members...
}
我需要的是:
- 在运行时创建一个
Foo2
类,该类具有所有Foo
类成员的副本. - 在
Foo2
类中,将Boo
方法替换为Boo2
方法,该方法的内容在一定程度上有所不同. - 创建
Foo2
的实例并调用Boo2
.
- Create a
Foo2
class at runtime which has a copy of allFoo
class members. - In
Foo2
class replaceBoo
method byBoo2
method that has its content alternated to some extent. - Create an instance of
Foo2
and invokeBoo2
.
感谢您的帮助.
推荐答案
如果不是这种框架的主要目的,则可以在运行时使用.NET AOP Framework事件来完成此操作.
You can do it at runtime using a .NET AOP Framework event if it is not the the main purpose of this kind of framework.
如果您的方法不是虚拟的,我将积极研究一种可以处理事件的新方法.
I actively work on a new one which can handle it event if your method is not virtual.
您可以查看 NConcern .NET运行时AOP框架
猴子补丁方面":
public class MonkeyPatch : IAspect
{
static public void Patch(MethodInfo oldMethod, MethodInfo newMethod)
{
//update monkey patch dictionary
MonkeyPatch.m_Dictionary[oldMethod] = newMethod;
//release previous monkey patch for target method.
Aspect.Release<MonkeyPatch>(oldMethod);
//weave monkey patch for target method.
Aspect.Weave<MonkeyPatch>(oldMethod);
}
static private Dictionary<MethodInfo, MethodInfo> m_Dictionary = new Dictionary<MethodInfo, MethodInfo>();
public IEnumerable<IAdvice> Advise(MethodInfo method)
{
if (MonkeyPatch.m_Dictionary.ContainsKey(_Method))
{
yield return Advice(MonkeyPatch.m_Dictionary[_Method]);
}
}
}
补丁:
static public void main(string[] args)
{
//create Boo2, a dynamic method with Boo signature.
var boo2 = new DynamicMethod("Boo2", typeof(void), new Type[] { typeof(Foo) }, typeof(Foo), true);
var body = boo2.GetILGenerator();
//Fill your ILGenerator...
body.Emit(OpCodes.Ret);
//Apply the patch
MonkeyPatch.Patch(typeof(Foo).GetMethod("Boo"), boo2);
}
在第二只手中,如果您只需要在原始通话后再打个电话,就可以达到AOP的目标,并且可以这样做...
in the second hand, if you just need to call something after the original call, you are in AOP aim and you can do it like that...
观察方面:
public class Observation : IAspect
{
static public void Observe(MethodInfo method, Action action)
{
//update observation dictionary
Observation.m_Dictionary[method] = action;
//release observation aspect for target method
Aspect.Release<Observation>(method);
//weave observation aspect for target method.
Aspect.Weave<Observation>(method);
}
static private Dictionary<MethodInfo, Action> m_Dictionary = new Dictionary<MethodInfo, Action>;
public IEnumerable<IAdvice> Advice(MethodInfo method)
{
if (Observation.m_Dictionary.ContainsKey(method))
{
yield return Advice.Basic.After(Observation.m_Dictionary[method]);
}
}
}
用例:
static public void main(string[] args)
{
Observation.Observe(typeof(Foo).GetMethod("Boo"), () => { /* paste here your notification code... */ });
}
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