c++ - 强制调用基类虚函数

Question

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
   }
}

有没有办法在不实际编写 Father::onLoad() 的情况下强制调用 onLoad？

欢迎使用黑客解决方案 :)

Answer 1

如果我理解正确的话，您希望这样每当调用被覆盖的函数时，必须始终首先调用基类实现。在这种情况下，您可以调查 template pattern .比如:

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()
        ...
    }
};