Yii2购物车 - 界面＆＃39;后端\ models \ CartPositionInterface＆＃39;未找到

Question

使用yii shopping cart时遇到问题。这是我的模特

<?php 
namespace backend\models;

use Yii;
use yii\db\ActiveRecord;
use yz\shoppingcart;

class Products extends ActiveRecord implements CartPositionInterface

Answer 1

指定CartPositionInterface的命名空间完整路径

use path_to_file\CartPositionInterface;

或

implements \path_to_file\CartPositionInterface