子类方法指针以法父参数C ++ [英] child class method pointer to method parent argument c++

问题描述

这可能是陌生的什么，我想看看，我会试图澄清尽可能。我使用的是在Ubuntu 14.04和C ++ 11 GCC 4.8。

it might be strange what i'm trying to see and i will try to clarify as much as possible. I'm using gcc 4.8 on ubuntu 14.04 and C++11.

我想试图做的是：

• 请A类


• 请在A级它获取作为参数的函数


• 一个指向同一个类中的一个成员


• 请新的B类从A继承


• 请B级的新方法



• 给一个指向类B的方法作为参数父类A的方法

• make a class A
• make a function in that class A which gets as argument
• a pointer to a class member of the same class
• make a new class B which inherits from A
• make a new method of class B

• give a pointer to that method of class B to a method of parentclass A as argument

class A{
    typedef void(A::*METHOD);        

    void executeMethod(METHOD arg){};
}

class B : A{

    void sampleMethod(){};

    void childMethod(){              

      this->executeMethod(&B::sampleMethod); //<== error
    }
}

然而，这使我在$ C $的cblock以下错误：

However this brings me the following error in codeblocks:

error: no matching function to call for 'B::executeMethod(void B::*)'

有没有解决这个办法吗？
还有什么我需要做的，说清楚你的，就是我要完成的？

Is there any way around this? Is there anything else i need to do to make it clear to you, what i'm trying to accomplish?

推荐答案

您不能直接调用方法，孩子从基类，但可以使用的模板：

You cannot directly call child method from a base class, but you can use template:

class A {
public:
    template<class T>
    void executeMethod( void (T::*method)() )
    {
        (static_cast<T *>( this )->*method)();
    }
};

class B : public A {
public:
    void sampleMethod() {}
    void childMethod() { executeMethod( &B::sampleMethod ); }
};

但更灵活的解​​决方案是使用的std ::功能和的std ::绑定为那么你就可以传方法这签名不匹配。

But more flexible solution would be to use std::function and std::bind as then you can pass methods which signature does not match.

class A {
public:
    typedef std::function<void()> Method;

    void executeMethod( const Method &method )
    {
        method();
    }
};

class B : public A {
public:
    void sampleMethod1() {}
    void sampleMethod2( int param ) {}

    void childMethod1() { executeMethod( std::bind( &B::sampleMethod1, this ); }
    void childMethod2() { executeMethod( std::bind( &B::sampleMethod2, this, 123 ); }
};

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