在更新记录中插入而不是覆盖新上传

Question

当我更新记录，即联系人时，附件（图像）会被覆盖。如何插入新附加的图像而不是覆盖旧的图像？请参阅下面的代码（我正在使用Yii 2.0 PHP框架）。

控制器

public function actionUpdate($id)
{   
    $session = Yii::$app->session;
    $model = $this->findModel($id);
    $cur_businessname = $model->business_name;
    $attachment = $model->attachment;
    $files = array();

    if ($model->load(Yii::$app->request->post())) {
        $model->attachment = UploadedFile::getInstances($model, 'attachment');

        if($model->attachment) {
            if (empty($model->attachment)) {
                $model->attachment = UploadedFile::getInstance($model, 'attachment');
                $path = 'assets/images/default.png';
                $model->attachment = $path;
            } else {                
                foreach ($model->attachment as $attachment) {
                    $path = 'archive/contact/'.$attachment->baseName.'.'.$attachment->extension;
                    $count = 0;
                    {
                        while(file_exists($path)) {
                           $path = 'archive/contact/'.$attachment->baseName.'_'.$count.'.'.$attachment->extension;
                           $count++;
                        }
                    }                        
                    $attachment->saveAs($path);
                    $files[] = $path; 
                }
                $model->attachment = implode(',', $files); 
            }
        } else {
            $model->attachment = $attachment;
        } 
        //$updatedAttachments = array_push($attachment,$path); 
        //var_dump($attachment);
        //exit;

        $model->save();

        if($model->save()) {
            Yii::$app->session->setFlash('success', "Success!");
        } else {
            Yii::$app->session->setFlash('error', "Contact Creation Failed!");
        }

        $model->refresh();
        return $this->redirect(['index', 'id' => $session['user_id']]);
    } else {            
        return $this->renderAjax('update', [
            'model' => $model,
        ]);
    }
}

查看

<?php
    if (!empty($model->attachment)) {
        $model->attachment = explode(',', $model->attachment);
        $file = '';
        foreach ($model->attachment as $attachment) {
            $file.= Html::img(Yii::$app->urlManager->baseUrl . '/'. $attachment, ['class'=>'file-preview-image', 'alt'=>'Attachment', 'title'=>'Attachment']).',';
        }
        echo FileInput::widget([
            'model' => $model,
            'attribute' => 'attachment[]',
            'options' => ['multiple' => true],
            'pluginOptions' => [
                'initialPreview'=>[ 
                    [$file,]
                ],
                'showCaption' => false,
                'showRemove' => false,
                'showUpload' => false,
                'browseClass' => 'btn btn-primary btn-block',
                'browseIcon' => '<i class="glyphicon glyphicon-camera"></i> ',
                'browseLabel' =>  'Attach Business Card',
                'maxFileCount' => 2,
                'allowedFileExtensions'=>['jpg','gif','png'], 
                'overwriteInitial' => true,
                'uploadAsync' => true,
                ],
            'options' => ['accept' => 'image/*', 'multiple' => true]
        ]);
    } else {
        echo FileInput::widget([
            'model' => $model,
            'attribute' => 'imageUrl[]',
            'options' => ['multiple' => true],
            'pluginOptions' => [
                'showCaption' => false,
                'showRemove' => false,
                'showUpload' => false,
                'maxFileCount' => 2,
                'browseClass' => 'btn btn-primary btn-block',
                'browseIcon' => '<i class="glyphicon glyphicon-camera"></i> ',
                'browseLabel' =>  'Attach Business Card',
                'allowedFileExtensions'=>['jpg','gif','png'], 
                ],
            'options' => ['accept' => 'image/*', 'multiple' => true]
        ]);
    }
?>

我尝试了array_push，但它没有用。 $attachment第6行的actionUpdate包含旧附件。现在，我无法在$attachment内使用if ($model->load(Yii::$app->request->post()))，因为它已经在发布/提交表单之后。

如何在不覆盖旧文件的情况下插入新附加的文件？您的意见/答案将会有很大的帮助！