PHP

Question

我想知道在 parent 和 child class 之间传递变量的最佳方式是什么，并一直更新这个 class class被执行。例如我有这个 parent class 里面执行的是 child class:

class My_Class {

   public $data;
   public $data2;

   public function __construct() {  
   }

   public function output() {
       $data['key1'] = 1;
       $data['key2'] = 2;
       $data2['key1'] = 'a';
       $data2['key2'] = 'b';
       $child_class = new Child_Class();
       $child_class->output();
       print_r($this->data); // only contains  key1 & key2, I want to get key3 and 4 also
       print_r($this->data2);
   }

}

class Child_Class extends My_Class {

   public function __construct() {  
   }

   public function output() {
       $data  = parent::$data; // want to get data array but it's empty
       $data2 = parent::$data2; // want to get data2 array but it's empty
       this->set_data();
   }

   public function set_data() {
       $this->data['key3'] = 3;
       $this->data['key4'] = 4;
       $this->data['key3'] = 'c';
       $this->data['key4'] = 'd';
   }


}

$class = new My_class();
$class->output();

目前我在parentclass里面执行childclass因为我需要填充parent[=27=的主要数据].这个class会根据一些变量执行childclass。

从 parent 到 child 和从 child 到 parent 继承和分配变量的正确方法是什么？如果我使用依赖注入来检索扩展 class 中的数据，我如何将变量分配给 parent class?

Answer 1

"Do you have an example" - 给你....

<?php
class My_Class {
    public $data = array('key1'=>1, 'key2'=>2);
    public $data2 = array('key1'=>'a', 'key2'=>'b');

    public function output() {
        echo "MyClass::output\r\n";
        print_r($this->data);
        print_r($this->data2);
    }
}


class Child_Class extends My_Class {

    public function __construct() {
        $this->data['key3'] = 3;
        $this->data['key4'] = 4;
        $this->data2['key3'] = 'c';
        $this->data2['key4'] = 'd';
    }

    public function output() {
        echo "Child_Class::output\r\n";
        parent::output();
    }
}

$class = new Child_Class();
$class->output();

打印

Child_Class::output
MyClass::output
Array
(
    [key1] => 1
    [key2] => 2
    [key3] => 3
    [key4] => 4
)
Array
(
    [key1] => a
    [key2] => b
    [key3] => c
    [key4] => d
)

另见：

https://en.wikipedia.org/wiki/Method_overriding
http://php.net/manual/en/keyword.parent.php
What is polymorphism, what is it for, and how is it used?
https://en.wikipedia.org/wiki/Inheritance_%28object-oriented_programming%29
https://en.wikipedia.org/wiki/Constructor_%28object-oriented_programming%29

Answer 2

我的问题是一个类型，而不是 $this->data 我写 $this->$data，$ 符号只需要在每个语句的开头。

我的第二个问题是在访问父 class 上的变量时省略了 $this-> 部分，从而为父 class 创建了局部范围的变量，该变量未与子 class 共享es，应该用$this->variable.

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extends

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