PHP子类访问父类中的对象
问题描述：
class bm_main {
public $db;
public function __construct(){
$this->db = new db();
}
}
class bm extends bm_main{
public function __construct($id){
$this->db = parent::$db;
$this->db->save($id);
}
}
How to access the $db object from parent class so i can use it in the child one
class bm_main {
public $ db;
public function __construct（）{
$ this-＆gt; db = new db（）;
}
}
class bm extends bm_main {
public function __construct（$ id）{
$ this-＆gt ; db = parent :: $ db;
$ this-＆gt; db-＆gt; save（$ id）;
}
}
code> pre>
如何 从父类访问$ db对象，以便我可以在子类中使用它 p>
div>
答
Call the parent constructor so the db class is instantiated:
public function __construct($id) {
parent::__construct();
$this->db->save($id);
}
The $db property is inherited by the subclass, and is public, so you can access it using $this->db.