File 如何在yii2视图中显示上传的文件并与之交互？

我在控制器中添加了文件上传功能，文件存储在指定的目录中，但更新、索引、视图等视图仅显示文件名。我需要一个链接或按钮与这个上传的文件进行交互。例如，按此链接打开文件，或同时下载此文件的按钮。你能帮我吗

型号：

public function rules()
{
    return [
    ...
        [['attachment'],'file'],
    ];
}

控制器：

public function actionCreate()
{
    $model = new Letter();

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

        $filename = pathinfo($model->attachment , PATHINFO_FILENAME);
        $ext = pathinfo($model->attachment , PATHINFO_EXTENSION);

        $newFname = $filename.'.'.$ext;

        $path=Yii::getAlias('@webroot').'/uploads/';
        if(!empty($newFname)){
            $model->attachment->saveAs($path.$newFname);
            $model->attachment = $newFname;
            if($model->save()){
                return $this->redirect(['view', 'id' => $model->id]);
            }
        }
    }
    return $this->render('create', [
        'model' => $model,
    ]);

表单视图：

<?php $form = ActiveForm::begin(['options' => ['enctype'=>'multipart/form-data']]); ?>
...

<?= $form->field($model, 'attachment')->fileInput() ?>

<div class="form-group">
    <?= Html::submitButton($model->isNewRecord ? 'Create' : 'Update', ['class' => $model->isNewRecord ? 'btn btn-success' : 'btn btn-primary']) ?>
</div>

<?php ActiveForm::end(); ?>

...

---

提前感谢。

更新您的表单视图，如下所示：

<?php $form = ActiveForm::begin(['options' => ['enctype'=>'multipart/form-data']]); ?>
...

<?= $form->field($model, 'attachment')->fileInput() ?>

 /*link to download file*/
<?if(!$model->isNewRecord):?>
<?= Html::a('Download file', ['download', 'id' => $model->id], ['class' => 'btn btn-primary']) ?>
<?endif;?>

<div class="form-group">
    <?= Html::submitButton($model->isNewRecord ? 'Create' : 'Update', ['class' => $model->isNewRecord ? 'btn btn-success' : 'btn btn-primary']) ?>
</div>


<?php ActiveForm::end(); ?>

在网格视图中：

 <?= GridView::widget([
'dataProvider' => $dataProvider,
'id'=>'mygrid',
'columns' => [
['class' => 'yii\grid\SerialColumn'],



[
'attribute'=>'attachment',
'format'=>'raw',
'value' => function($data)
{
    return
    Html::a('Download file', ['letter/download', 'id' => $data->id], ['class' => 'btn btn-primary']);

}
],

],
]); ?>

您好，谢谢您的回答。它表示未定义的变量$model。我应该将其添加为参数还是创建全局变量$model=new Letter（）？@VitalyPark更新的控制器代码请立即检查表单视图中的if语句是否出错。“isNewRecord:？>”部分在视图中看起来像一个简单的文本。@VitalyPark请指定该错误代码或消息。

 <?= GridView::widget([
'dataProvider' => $dataProvider,
'id'=>'mygrid',
'columns' => [
['class' => 'yii\grid\SerialColumn'],



[
'attribute'=>'attachment',
'format'=>'raw',
'value' => function($data)
{
    return
    Html::a('Download file', ['letter/download', 'id' => $data->id], ['class' => 'btn btn-primary']);

}
],

],
]); ?>