从父范围访问子属性 [英] Access child property from parent scope

问题描述

我需要一个父类来访问其子属性:

I need a parent class to access its child properties:

class Parent {
  private $_fields = null;

  public function do_something() {
    // Access $_fields and $child_var here
  }
}

class Child extends Parent {
  private $child_var = 'hello';
}

$child = new Child();
$child->do_something();

从子作用域修改$_fields时，它仍在父作用域中null.当尝试使用$this->child_var从父范围访问$ child_var时，它当然是未定义的.

When $_fields is modified from the child scope, it's still null in the parent scope. When trying to access $child_var from parent scope using $this->child_var, it's of course undefined.

我没有找到像功能集"这样的东西会被复制到子类中.

I didn't find anything like a "function set" that would just be copied in the child class...

推荐答案

看看有关可见性.

基本上，您不能访问父级的private属性/方法，父级也不能访问其子级的属性/方法.但是，您可以改为声明您的属性/方法protected.

Basically, you cannot access parent's private properties/methods nor can the parent access its child's. However, you can declare your property/method protected instead.

class Parent {
    protected $_fields = null;

    public function do_something() {
        // Access $_fields and $child_var here
    }
}

class Child extends Parent {
    protected $child_var = 'hello';
}

$child = new Child();
$child->do_something();

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