php-di中的多构造函数参数注入

Question

我正在尝试使用PHP-DI，但我没有完全成功。在我的简单扫描中，在Wordpress主题中的控制器需要在构造函数中注入一个PostService和一个CategoryService：

class IndexController extends ChesterBaseController {
    private $_postservice;
    private $_categoryService;
    public function __construct(PostService $postservice, CategoryService $categoryService){
        var_dump($postservice);
        var_dump($categoryService);
        parent::__CONSTRUCT();
        $this->$_categoryService = $categoryService;
        $this->$_postservice = $postservice;
        var_dump($this->$_postservice);
        var_dump($this->$_categoryService);

    }
    public function Index(){
        $firstRowPost = $this->$_postservice->GetLastPostByCategory('video');
        // ...
        echo $this->renderPage('index', $vm);
    }
}

这是Index.php中容器的入口点：

require_once 'vendor/autoload.php';
require_once dirname(__FILE__).'/mvc/controllers/index_controller.php';
require_once dirname(__FILE__).'/mvc/services/categoryService.php';
require_once dirname(__FILE__).'/mvc/services/postService.php';
use DI\Container;
use DI\ContainerBuilder;

$builder = new DI\ContainerBuilder();
$builder->addDefinitions(['config.php']);
$container = $builder->build();
$indexController = $container->get('IndexController');
$indexController->Index();

以及包含定义的“config.php”：

return [
    'PostService' => \DI\object('PostService'),
    'CategoryService' => \DI\object('CategoryService'),
    'IndexController' => \DI\object()->constructor(DI\get('PostService'),DI\get('CategoryService'))
];

这是执行结果：

C:\xampp\apps\wordpress\htdocs\wp-content\themes\chester-nanalab\mvc\controllers\index_controller.php:10:对象(PostService)3005 C:\xampp\apps\wordpress\htdocs\wp-content\themes\chester-nanalab\mvc\controllers\index_controller.php:11: object(CategoryService)3006 C:\xampp\apps\wordpress\htdocs\wp-content\themes\chester-nanalab\mvc\controllers\index_controller.php:15: object(CategoryService)3006C:\xampp\apps\wordpress\htdocs\wp-content\themes\chester-nanalab\mvc\controllers\index_controller.php:16: object(CategoryService)3006

因此：

致命错误:未定义的错误:调用第19行C:\xampp\apps\wordpress\htdocs\wp-content\themes\chester-nanalab\mvc\controllers\index_controller.php中的未定义方法CategoryService::GetLastPostByCategory()

ლ(ಠ益ಠლ)╯

但是，如果我改变任务的顺序：

public function __construct(PostService $postservice,CategoryService $categoryService){
    var_dump($postservice);
    var_dump($categoryService);
    parent::__CONSTRUCT();
    $this->$_categoryService = $categoryService;
    $this->$_postservice = $postservice;
    var_dump($this->$_postservice);
    var_dump($this->$_categoryService);
}

我能读到：

C:\xampp\apps\wordpress\htdocs\wp-content\themes\chester-nanalab\mvc\controllers\index_controller.php:10:对象(PostService)3005 C:\xampp\apps\wordpress\htdocs\wp-content\themes\chester-nanalab\mvc\controllers\index_controller.php:11: object(CategoryService)3006 C:\xampp\apps\wordpress\htdocs\wp-content\themes\chester-nanalab\mvc\controllers\index_controller.php:17: object(PostService)3005C:\xampp\apps\wordpress\htdocs\wp-content\themes\chester-nanalab\mvc\controllers\index_controller.php:18: object(PostService)3005

​

​

(╯°-°)╯︵┻━┻？它起作用了!有人能向我解释一下发生了什么吗？

提前谢谢。

Answer 1

问题是，您将对象属性调用为$this->$property。属性的访问方式类似于此$this->property，但定义了VISIBILITY $property;

因此，您应该将代码更改为

class IndexController extends ChesterBaseController {
    private $_postservice;
    private $_categoryService;
    public function __construct(PostService $postservice, CategoryService $categoryService){
      var_dump($postservice);
      var_dump($categoryService);
      parent::__construct();
      $this->_categoryService = $categoryService;
      $this->_postservice = $postservice;
      var_dump($this->_postservice);
      var_dump($this->_categoryService);

    }
    public function Index(){
        $firstRowPost = $this->_postservice->GetLastPostByCategory('video');
       // ...
        echo $this->renderPage('index', $vm);
    }
}

对于parent，它是不同的，因为您使用的是static访问器(您不是以静态的方式获取属性，但它是实现它的方法) parent::$property。

请记住，对于任何__construct，它都是小写的魔术法。

您可以获得更多关于类和对象这里的信息。