Question

class Grandfather {

    protected function stuff() {
        // Code.
    } 
}

class Dad extends Grandfather {
    function __construct() {
        // I can refer to a member in the parent class easily.
        parent::stuff();
    }
}

class Kid extends Dad {
        // How do I refer to the stuff() method which is inside the Grandfather class from here?
}

我怎样才能在Kid课程中引用祖父班的成员？

我的第一个想法是Classname::method()但有一个关键字可用，例如self或parent？

Answer 1

$this->stuff() 要么 Grandfather::stuff()

使用此方法调用将在继承级别的顶部调用::stuff()方法（在您的示例中，它是Dad::stuff()，但您不能覆盖::stuff课程中的Dad，因此它会Grandfather::stuff()）< / p>

和Class::method()将调用精确类方法

示例代码：

    <?php
class Grandfather {

    protected function stuff() {
        echo "Yeeeh";
        // Code.
    } 
}

class Dad extends Grandfather {
    function __construct() {
        // I can refer to a member in the parent class easily.
        parent::stuff();
    }
}

class Kid extends Dad {
    public function doThatStuff(){
        Grandfather::stuff();
    }
      // How do I refer to the stuff() method which is inside the Grandfather class from here?
}
$Kid = new Kid();
$Kid->doThatStuff();

＆＃34; Yeeeh＆＃34;将被输出2次。因为Dad的构造函数（在Kid类中未被覆盖）类调用Grandfather::stuff()和Kid::doThatStuff()调用它

Answer 2

如果stuff()在类层次结构中无法覆盖，则可以使用$this->stuff()
如果要在stuff()中覆盖Dad，则必须使用类名调用该函数，例如Grandfather::stuff()
如果在stuff()中覆盖Kid，您可以通过parent::stuff()

Answer 3

如果您想调用祖父:: stuff方法，可以使用Grandfather::stuff()课程中的Kid执行此操作。

看看这个example。

是否有一个关键字引用PHP中祖父类的成员？

3 个答案: