yii2 and mssql insert varbinary into model

PHP Snippet 1:

public function actionAjupd()
{
    $this->getuser();

    $model = new Allfiles();
  //  mb_internal_encoding( 'UTF-8' );

    if ($model->load(Yii::$app->request->post())){
        $x=$model->f_content;
        $tmpfile=UploadedFile::getInstance($model, 'f_content');
       $h=
       (binary)(file_get_contents($tmpfile->tempName));
      // var_dump($model); 
       $model->nomefile=basename($tmpfile);
       $model->origine='S';
       $model->estensione=pathinfo($tmpfile ,PATHINFO_EXTENSION);
        $model->setAttribute('f_content','');
       $model->save(false); 
       $id=$model->getPrimaryKey();
       $connection = Yii::$app->getDb();
       $command = $connection->createCommand("
       update all_files set f_content=convert(
        VARBINARY(max) ,  
        :contenuto ,1) where id=:id
       
       ",[':id'=>$id,':contenuto'=>'0x'.bin2hex($h)]);
        $command->execute();
       //\Yii::$app->response->format = Response::FORMAT_JSON;
       return $this->redirect(Yii::$app->request->referrer ?: Yii::$app->homeUrl);
    }

    return $this->renderAjax('create', [
        'model' => $model,
    ]);
}