控制器层级5.3中的全局变量

Question

如何定义全局变量以在所有函数控制器中使用

class TestController extends Controller
{
    private $x;

    public function index()
    {
        $this->$x ='22';
    }            

    public function send_message()
    {
        echo $this->$x;
    }
}

Answer 1

写$this->x而不是$this->$x

class TestController extends Controller
{
    private $x;

    public function index()
    {
        $this->x ='22';
    }

    public function send_message()
    {
        echo $this->x;
    }
}