Dependency Injection در PHP به سادگی با یک مثال توضیح داده شده است

class Vehicle {
    private $make;
    private $model;

    public function __construct($make, $model){
        $this->make = $make;
        $this->model = $model;
    }
}

class Garage {
    private $vehicle;
    private $sku;

    public function __construct($sku, $vehicleMake, $vehicleModel){
        $this->vehicle = new Vehicle($vehicleMake, $vehicleModel);
        $this->sku = $sku;
    }
}

class ElectricVehicle extends Vehicle {
    private $batteryCapacity;

    public function __construct($make, $model, $batteryCapacity){
        parent::__construct($make, $model);
        $this->batteryCapacity = $batteryCapacity;
    }

    public function getBatteryCapacity() {
        ....
    }
}

class Garage {
    private $vehicle;
    private $sku;

    public function __construct($sku, $make, $model, $batteryCapacity = null){
        if ($batteryCapacity) {
            $this->vehicle = new ElectricVehicle($make, $model, $batteryCapacity);
        } else {
            $this->vehicle = new Vehicle($make, $model);
        }
        $this->sku = $sku;
    }
}

class Vehicle {
    private $make;
    private $model;

    public function __construct($make, $model){
        $this->make = $make;
        $this->model = $model;
    }
}

class ElectricVehicle extends Vehicle {
    private $batteryCapacity;

    public function __construct($make, $model, $batteryCapacity){
        parent::__construct($make, $model);
        $this->batteryCapacity = $batteryCapacity;
    }

    public function getBatteryCapacity() {
        ...
    }
}

class Garage {
    private $vehicle;
    private $sku;

    public function __construct($sku, Vehicle $vehicle){
        $this->vehicle = $vehicle;
        $this->sku = $sku;
    }
}

// Create an instance of Vehicle
$vehicle = new Vehicle('Toyota', 'Corolla');
$garage = new Garage('SKU123', $vehicle);

// Create an instance of ElectricVehicle
$electricVehicle = new ElectricVehicle('Tesla', 'Model S', 100);
$electricGarage = new Garage('SKU124', $electricVehicle);