PHP實例
public function __get($name)
{
  $getter = 'get' . $name;
  if (method_exists($this, $getter)) {
    return $this->$getter();
  } else {
    // 注意這個 else 分支的內容,正是與 yii\base\Object::__get() 的
    // 不同之處
    $this->ensureBehaviors();
    foreach ($this->_behaviors as $behavior) {
      if ($behavior->canGetProperty($name)) {
        // 屬性在行為中須為 public.否則不可能通過下面的形式拜訪呀.
        return $behavior->$name;
      }
    }
  }
  if (method_exists($this, 'set' . $name)) {
    throw new InvalidCallException('Getting write-only property: ' .
      get_class($this) . '::' . $name);
  } else {
    throw new UnknownPropertyException('Getting unknown property: ' .
      get_class($this) . '::' . $name);
  }
}

PHP實例
public function __call($name, $params)
{
  $this->ensureBehaviors();
  foreach ($this->_behaviors as $object) {
    if ($object->hasMethod($name)) {
      return call_user_func_array([$object, $name], $params);
    }
  }
  throw new UnknownMethodException('Calling unknown method: ' .
    get_class($this) . "::$name()");
}

PHP實例
public function canGetProperty($name, $checkVars = true)
{
  return method_exists($this, 'get' . $name) || $checkVars &&
    property_exists($this, $name);
}
public function canSetProperty($name, $checkVars = true)
{
  return method_exists($this, 'set' . $name) || $checkVars &&
    property_exists($this, $name);
}
public function hasMethod($name)
{
  return method_exists($this, $name);
}

PHP實例
class Foo
{
  public function __construct(Bar $bar)
  {
  }
}
$foo = $container->get('Foo');
// 上面的代碼等價于：
$bar = new Bar;
$foo = new Foo($bar);

PHP實例
use yii\base\Object;
class Foo extends Object
{
  public $bar;
  private $_qux;
  public function getQux()
  {
    return $this->_qux;
  }
  public function setQux(Qux $qux)
  {
    $this->_qux = $qux;
  }
}
$container->get('Foo', [], [
  'bar' => $container->get('Bar'),
  'qux' => $container->get('Qux'),
]);

PHP實例
$container->set('Foo', function () {
  return new Foo(new Bar);
});
$foo = $container->get('Foo');

PHP實例
$container = new \yii\di\Container;
// 注冊一個同類名一樣的依賴關系,這個可以省略.
$container->set('yii\db\Connection');
// 注冊一個接口
// 當一個類依賴這個接口時,相應的類會被初始化作為依賴對象.
$container->set('yii\mail\MailInterface', 'yii\swiftmailer\Mailer');
// 注冊一個別名.
// 你可以使用 $container->get('foo') 創建一個 Connection 實例
$container->set('foo', 'yii\db\Connection');
// 通過配置注冊一個類
// 通過 get() 初始化時,配置將會被使用.
$container->set('yii\db\Connection', [
  'dsn' => 'mysql:host=127.0.0.1;dbname=demo',
  'username' => 'root',
  'password' => '',
  'charset' => 'utf8',
]);
// 通過類的配置注冊一個別名
// 這種情況下,需要通過一個 “class” 元素指定這個類
$container->set('db', [
  'class' => 'yii\db\Connection',
  'dsn' => 'mysql:host=127.0.0.1;dbname=demo',
  'username' => 'root',
  'password' => '',
  'charset' => 'utf8',
]);
// 注冊一個 PHP 回調
// 每次調用 $container->get('db') 時,回調函數都會被執行.
$container->set('db', function ($container, $params, $config) {
  return new \yii\db\Connection($config);
});
// 注冊一個組件實例
// $container->get('pageCache') 每次被調用時都會返回同一個實例.
$container->set('pageCache', new FileCache);

PHP實例
$container->setSingleton('yii\db\Connection', [
  'dsn' => 'mysql:host=127.0.0.1;dbname=demo',
  'username' => 'root',
  'password' => '',
  'charset' => 'utf8',
]);

PHP實例
// "db" 是前面定義過的一個別名
$db = $container->get('db');
// 等價于： $engine = new \app\components\SearchEngine($apiKey, ['type' => 1]);
$engine = $container->get('app\components\SearchEngine', [$apiKey], ['type' => 1]);

PHP實例
namespace app\models;
use yii\base\Object;
use yii\db\Connection;
use yii\di\Container;
interface UserFinderInterface
{
  function findUser();
}
class UserFinder extends Object implements UserFinderInterface
{
  public $db;
  public function __construct(Connection $db, $config = [])
  {
    $this->db = $db;
    parent::__construct($config);
  }
  public function findUser()
  {
  }
}
class UserLister extends Object
{
  public $finder;
  public function __construct(UserFinderInterface $finder, $config = [])
  {
    $this->finder = $finder;
    parent::__construct($config);
  }
}
$container = new Container;
$container->set('yii\db\Connection', [
  'dsn' => '...',
]);
$container->set('app\models\UserFinderInterface', [
  'class' => 'app\models\UserFinder',
]);
$container->set('userLister', 'app\models\UserLister');
$lister = $container->get('userLister');
// 等價于:
$db = new \yii\db\Connection(['dsn' => '...']);
$finder = new UserFinder($db);
$lister = new UserLister($finder);

PHP實例
\Yii::$container->set('yii\widgets\LinkPager', ['maxButtonCount' => 5]);

PHP實例
echo \yii\widgets\LinkPager::widget();

PHP實例
echo \yii\widgets\LinkPager::widget(['maxButtonCount' => 20]);

PHP實例
namespace app\controllers;
use yii\web\Controller;
use app\components\BookingInterface;
class HotelController extends Controller
{
  protected $bookingService;
  public function __construct($id, $module, BookingInterface $bookingService, $config = [])
  {
    $this->bookingService = $bookingService;
    parent::__construct($id, $module, $config);
  }
}