Yii2-GridView 自定义关联字段带搜索和排序功能

要在订单（Order）视图的gridview中显示出客户（Customer）姓名，并使其具有与其它字段相同的排序和搜索功能。

数据库结构
订单表order含有字段customer_id 与 客户表customer的id字段关联

首先确保在Order Model中包含以下代码：

public function getCustomer()
{
    return $this->hasOne(Customer::className(), ["id" => "customer_id"]);
}

用gii会自动生成此代码；

第一步：
在OrderSearch添加一个$customer_name变量

class OrderSearch extends Order
{
    public $customer_name; 
}

第二步：
修改OrderSearch中的search函数

public function search($params)
{
    $query =  Order::find();
    $query->joinWith(["customer"]); //添加代码
    $dataProvider = new ActiveDataProvider([
        "query" => $query,   //$query必须返回ActiveQuery
    ]);
    
    $dataProvider->setSort([
        "attributes" => [
            /* 指定其它字段 */    
            /* 加入 */
            /*=============*/
            "customer_name" => [
                "asc" => ["customer.customer_name" => SORT_ASC],  //table.字段，若行记录字段名唯一，可略table
                "desc" => ["customer.customer_name" => SORT_DESC],
                "label" => "Customer Name"
            ],
            /*=============*/
        ]
    ]); 

    if (!($this->load($params) && $this->validate())) {
        return $dataProvider;
    }

    $query->andFilterWhere([
        "id" => $this->id,
        "user_id" => $this->user_id,
        "customer_id" => $this->customer_id,
        "order_time" => $this->order_time,
        "pay_time" => $this->pay_time,
    ]);

    $query->andFilterWhere(["like", "status", $this->status]);
    $query->andFilterWhere(["like", "customer.customer_name", $this->customer_name]) ;   //添加代码,table.字段，若行记录字段名唯一，可略table
 
    return $dataProvider;
}

第三步：
修改order/index视图的gridview

<?= GridView::widget([
    "dataProvider" => $dataProvider,
    "filterModel" => $searchModel,
    "columns" => [
        ["class" => "yiigridSerialColumn"],
        "id",
        "customer_id",  
        "status",
        ["label"=>"客户",  "attribute" => "customer_name",  "value" => "customer.customer_name" ],//添加代码，table.字段，若行记录字段名唯一，可略table

        ["class" => "yiigridActionColumn"],
    ],
]); ?>