强制调用基类虚函数 [英] Force calling base class virtual function

问题描述

我有一些这样的事件

class Granpa // this would not be changed, as its in a dll and not written by me
{
public:

   virtual void onLoad(){}

}

class Father :public Granpa // my modification on Granpa
{
public:

    virtual void onLoad()
    {
       // do important stuff
    }

}

class Child :public Father// client will derive Father
{

   virtual void onLoad()
   {
       // Father::onLoad(); // i'm trying do this without client explicitly writing the call

       // clients code
   }
}

有没有办法强制调用onLoad而不实际写 Father :: onLoad（）？

Is there a way to force calling onLoad without actually writing Father::onLoad()?

欢迎使用Hackish解决方案：）

Hackish solutions are welcome :)

推荐答案

如果我理解正确，被调用，基类实现必须总是先调用。在这种情况下，您可以调查 模板模式 。类似的东西：

If I understand correctly, you want it so that whenever the overriden function gets called, the base-class implementation must always get called first. In which case, you could investigate the template pattern. Something like:

class Base
{
public:
    void foo() {
        baseStuff();
        derivedStuff();
    }

protected:
    virtual void derivedStuff() = 0;
private:
    void baseStuff() { ... }
};

class Derived : public Base {
protected:
    virtual void derivedStuff() {
        // This will always get called after baseStuff()
        ...
    }
};

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