C#在运行时更改类方法

Question

我需要扩展实例的行为,但我无法访问该实例的原始源代码.例如:

/* I don't have the source code for this class, only the runtime instance */
Class AB
{
  public void execute();
}

在我的代码中,我会截取每个执行调用,计算一些sutff然后调用原始执行,类似于

/* This is how I would like to modify the method invokation */
SomeType m_OrgExecute;

{
    AB a = new AB();
    m_OrgExecute = GetByReflection( a.execute );
    a.execute = MyExecute;
}

void MyExecute()
{
    System.Console.Writeln( "In MyExecute" );
    m_OrgExecute();
}

那可能吗？

有没有人有这个问题的解决方案？

Answer 1

看起来你想要Decorator模式.

class AB
{
   public void execute() {...}
}

class FlaviosABDecorator : AB
{
   AB decoratoredAB;

   public FlaviosABDecorator (AB decorated)
   {
       this.decoratedAB = decorated;
   }

   public void execute()
   {
       FlaviosExecute();  //execute your code first...
       decoratedAB.execute();
   }

   void FlaviosExecute() {...}
}

然后,您必须修改AB使用该对象的代码.

//original code
//AB someAB = new AB();

//new code
AB originalAB = new AB();
AB someAB = new FlaviosABDecorotor(originalAB);

/* now the following code "just works" but adds your method call */