How to save data with file upload in YII2?

Question

Yii

Installed a widget for downloading files from Kartik. But in parallel with loading the file, it is necessary to save the data in the database.
But something doesn't work for me.
Here is the model:

class UploadFiles extends Model
{
    /**
     * @var UploadedFile[]
     */

       public $dataFiles;
       public $filePath;
       public $class;
    public  function __construct()
    {
        $this->filePath='uploads_files/';
    }

    public function rules()
    {
        return [
             [['class'],'string'],
             [['dataFiles'], 'file', 'skipOnEmpty' => false, 'extensions' => 'txt, csv', 'maxFiles' => 4,'checkExtensionByMimeType' => false],
        ];
    }

    public function upload()
    {
        if ($this->validate()) {
            foreach ($this->dataFiles as $file) {
                $file->saveAs($this->filePath . $file->baseName . '.' . $file->extension);
                if(ImportFile::findOne(['file'=>$file->baseName])){
                    return false;
                }else{
                    $model_file=new ImportFile();
                    $model_file->file=$file->baseName;
                    $model_file->url=$file->extension;
                    $model_file->path=$this->filePath;
                    $model_file->integrity=0;
                    $model_file->class=$this->class;
                    $model_file->save();
                }

            }
            return true;
        } else {
            return false;
        }
    }
}

Here is the form:

$model=new \app\models\UploadFiles();
            $form = ActiveForm::begin(['action' => ['/laboratory/flash-analizator/upload'],'options' => ['enctype' => 'multipart/form-data']]);
            echo $form->field($model, 'class')->widget(Select2::classname(), [
                'data' =>['сlass_1'=>"Обработчик 1",'class_2'=>"Обработчик 2"],
                'options' => ['placeholder' => 'Select a state ...'],
                'name' => 'class',
                'pluginOptions' => [
                    'allowClear' => true
                ],
            ]);

        echo $form->field($model, 'dataFiles')->label('Выбранный файл')->widget(FileInput::classname(),[
            'id'=>'file',
            'name' => 'file-input',
            'disabled' => false,
            'language' => 'ru',
            'pluginOptions' => [
                'uploadUrl' => Url::to(['/laboratory/flash-analizator/upload']),
                'showPreview' => false,
            ],
        ]);
        ActiveForm::end();

Controller:

public function actionUpload()
    {
        if(Yii::$app->request->isPost){

            $model = new UploadFiles();
            $model->load(Yii::$app->request->post());


                $model->dataFiles = UploadedFile::getInstances($model, 'dataFiles');
             if ($model->upload()) {
                    return true;
                }else{
                    return Json::encode([
                        'error' => 'Ошибка загрузки файла'
                    ]);
                }
        }
    }

Where is the mistake?