Php 更新时如何设置yii2中数组对象的多选值

我有一个表，它有多个参考ohter表，如

user
id         name         email
categories
id         title
user_categories
user_id    category_id

在这里，用户将拥有多个与其关联的类别

我能够通过以下新记录成功保存这些记录

查看文件：

echo $form->field($package_categories, 'category_id')->dropDownList( ArrayHelper::map(
StudyMaterialCategories::find()->all(), 'id', 'title'), 
['multiple' => true]
);

$model = new Packages();
$package_categories = new PackageCategories();
$request = Yii::$app->request;
if ($request->isPost) {
    $transaction = Yii::$app->db->beginTransaction();
    try {
        $post = $request->post();
        $model->load($post);
        $model->save();
        foreach ($post['PackageCategories']['category_id'] as $key => $value) {
            $package_categories = new PackageCategories();
            $package_categories->category_id = $value;
            $package_categories->package_id = $model->id;
            $package_categories->save();
        }
        $transaction->commit();
        return $this->redirect(['view', 'id' => $model->id]);
    } catch (Exception $ex) {
        $transaction->rolback();
        Yii::$app->session->setFlash("error", $ex->getMessage());
    }
}

保存新记录：

echo $form->field($package_categories, 'category_id')->dropDownList( ArrayHelper::map(
StudyMaterialCategories::find()->all(), 'id', 'title'), 
['multiple' => true]
);

$model = new Packages();
$package_categories = new PackageCategories();
$request = Yii::$app->request;
if ($request->isPost) {
    $transaction = Yii::$app->db->beginTransaction();
    try {
        $post = $request->post();
        $model->load($post);
        $model->save();
        foreach ($post['PackageCategories']['category_id'] as $key => $value) {
            $package_categories = new PackageCategories();
            $package_categories->category_id = $value;
            $package_categories->package_id = $model->id;
            $package_categories->save();
        }
        $transaction->commit();
        return $this->redirect(['view', 'id' => $model->id]);
    } catch (Exception $ex) {
        $transaction->rolback();
        Yii::$app->session->setFlash("error", $ex->getMessage());
    }
}

到目前为止，它正在成功运行

但是我在更新表格的时候卡住了。问题部分是下拉列表。如果我带着对象数组，如何根据数据库设置多个选定选项。 看看下面的代码

$package_categories = PackageCategories::find()
->where('package_id=:package_id', ['package_id' => $id])->all();
if (count($package_categories) < 1) {
    $package_categories = new PackageCategories();
}
$request = Yii::$app->request;
if ($request->isPost) {
    $transaction = Yii::$app->db->beginTransaction();
    try {
        $post = $request->post();
        $model->load($post);
        $model->save();
        $package_categories = new PackageCategories();
        $package_categories->deleteAll(
            "package_id=:package_id", 
            [':package_id' => $model->id]
        );
        foreach ($post['PackageCategories']['category_id'] as $key => $value) {
            $package_categories = new PackageCategories();
            $package_categories->category_id = $value;
            $package_categories->package_id = $model->id;
            $package_categories->save();
        }
        $transaction->commit();
        return $this->redirect(['view', 'id' => $model->id]);
    } catch (Exception $ex) {
        $transaction->rolback();
        Yii::$app->session->setFlash("error", $ex->getMessage());
    }
}

$package\u categories=PackageCategories:：find（）
->其中（'package_id=：package_id'，['package_id'=>$id]）->all（）；
if（计数（$package_categories）<1）{
$package_categories=新的PackageCategories（）；
}
$request=Yii:：$app->request；
如果（$request->isPost）{
$transaction=Yii:：$app->db->beginTransaction（）；
试一试{
$post=$request->post（）；
$model->load（$post）；
$model->save（）；
$package_categories=新的PackageCategories（）；
$package\u categories->deleteAll(
“package_id=：package_id”，
['：package_id'=>$model->id]
);
foreach（$key=>value的post['PackageCategories']['category\u id']as$key）{
$package_categories=新的PackageCategories（）；
$package\u categories->category\u id=$value；
$package\u categories->package\u id=$model->id；
$package_categories->save（）；
}
$transaction->commit（）；
返回$this->redirect（['view'，'id'=>$model->id]）；
}捕获（例外$ex）{
$transaction->rolback（）；
Yii:：$app->session->setFlash（“错误”、$ex->getMessage（））；
}
}

---

如果我试图获取数组

$package\u categories

的第一个对象，该对象只能设置所选的一个选项

，这是一个模型类

许可证的示例代码，它通过
许可证
（透视表模型）与
活动
有
多对多
关系

示范班活动

public class Permit extends \yii\db\ActiveRecord {
    public $activities_ids;
    ...
    public function rules() {
        return [
            ...
            [['activities_ids'], 'safe'],
            ...
        ];
    }
    ...
    // Method called after record is saved, be it insert or update.
    public function afterSave($insert, $changedAttributes) {
        // If this is not a new record, unlink all records related through relationship 'activities'
        if(!$this->isNewRecord) {
            // We unlink all related records from the 'activities' relationship.
            $this->unlinkAll('activities', true);
            // NOTE: because this is a many to many relationship, we send 'true' as second parameter
            // so the records in the pivot table are deleted. However on a one to many relationship
            // if we send true, this method will delete the records on the related table. Because of this,
            // send false on one to many relationships if you don't want the related records deleted.
        }

        foreach($this->activities_ids as $activity_id) {
            // Find and link every model from the array of ids we got from the user.
            $activity = Activity::findOne($activity_id);
            $this->link('activities', $activity);
        }

        parent::afterSave($insert, $changedAttributes);
    }
    ...
    // Declare relationship with Activity through the pivot table permitActivity
    public function getActivities(){
        return $this->hasMany(Activitiy::className(), ['id' => 'activity_id'])
            ->viaTable('permitActivity',['permit_id' => 'id']);
    }
    ...
    public function afterFind(){
        parent::afterFind();
        $this->activities_id = ArrayHelper::getColumn($this->activities, 'id');
    }
}

这样，模型类负责使用透视表创建和更新关系

最重要的是正确声明relationship方法

编辑

这是使用的视图的一个示例。我真的不知道dropDownList是否支持多个选择，但是Select2有很多有用的功能，我通常使用它而不是其他选项

echo $form->field($model, 'activities')->widget(Select2::classname(), [
    'data' => $data,
    'options' => [
        'placeholder' => '...'
    ],
    'pluginOptions' => [
        'allowClear' => true,
        'multiple' => true,
    ],
]);

我的问题是如何在视图中设置选中的多个项目在我的示例中，多个项目字段是
activities\u ids
给我一个示例在视图中显示，比如$form->field（$modal_obj，'attribute_name'）->dropdownlist（$items，['multiple'=>true]），我认为小部件中的$data变量是数组，但我的问题是，当我们在更新表单中时，如何将两个选项设置为选中？若要在“多重选择”中显示选定的多个项目，只需将值设置为用于显示“多重选择”的模型字段的数组。