Input image in Yii2 Dynamic Form always null - image

Question

I want to make dynamic input that save an image to my website.
I use yii2-dynamicform and Kartik input file extension. But, it always save it as null.
Thank you for your help
Ps : ... is other part of my code that not relevant with this question. :)
In controller :
<?php
namespace frontend\controllers;
use Yii;
use common\models\Election;
use common\models\ElectionSearch;
use common\models\Model;
use common\models\Kandidat;
use yii\web\Controller;
use yii\web\NotFoundHttpException;
use yii\filters\VerbFilter;
use yii\data\ActiveDataProvider;
use yii\web\Session;
use yii\web\UploadedFile;
use yii\helpers\ArrayHelper;
class ElectionController extends Controller
{
...
public function actionCreate()
{
$model = new Election();
$modelsKandidat = [new Kandidat];
if ($model->load(Yii::$app->request->post())){
$model->save();
$modelsKandidat = Model::createMultiple(Kandidat::classname());
Model::loadMultiple($modelsKandidat, Yii::$app->request->post());
// validate all models
$valid = $model->validate();
$valid = Model::validateMultiple($modelsKandidat) && $valid;
if ($valid) {
$transaction = \Yii::$app->db->beginTransaction();
try {
if ($flag = $model->save(false)) {
foreach ($modelsKandidat as $modelKandidat) {
$modelKandidat->id_election = $model->id_election;
if($modelKandidat->file = UploadedFile::getInstance($modelKandidat,'file'))
{
$imageName = date('dmyhis_').$modelKandidat->id_election;
$modelKandidat->file->saveAs('../../common/file/fotokandidat/'.$imageName.'.'.$modelKandidat->file->extension);
$modelKandidat->foto = $imageName.'.'.$modelKandidat->file->extension;
}
if (! ($flag = $modelKandidat->save(false))) {
$transaction->rollBack();
break;
}
}
}
if ($flag) {
$transaction->commit();
return $this->redirect(['view', 'id' => $model->id_election]);
}
} catch (Exception $e) {
$transaction->rollBack();
}
}
} else {
return $this->render('create', [
'model' => $model,
'modelsKandidat' => $modelsKandidat,
]);
}
}
...
}
In _form :
<?php
use yii\helpers\Html;
use yii\widgets\ActiveForm;
use kartik\file\FileInput;
use yii\helpers\ArrayHelper;
use dosamigos\datepicker\DatePicker;
use wbraganca\dynamicform\DynamicFormWidget;
?>
<div class="election-form">
<?php $form = ActiveForm::begin(['options'=>['enctype'=>'multipart/form-data', 'id' => 'dynamic-form']]); ?>
...
<!-- mulai input kandidat !-->
<div class="row">
<div class="panel panel-default">
<div class="panel-heading"><h4><i class="glyphicon glyphicon-envelope"></i>Vote</h4></div>
<div class="panel-body">
<?php DynamicFormWidget::begin([
'widgetContainer' => 'dynamicform_wrapper', // required: only alphanumeric characters plus "_" [A-Za-z0-9_]
'widgetBody' => '.container-items', // required: css class selector
'widgetItem' => '.item', // required: css class
'limit' => 4, // the maximum times, an element can be cloned (default 999)
'min' => 1, // 0 or 1 (default 1)
'insertButton' => '.add-item', // css class
'deleteButton' => '.remove-item', // css class
'model' => $modelsKandidat[0],
'formId' => 'dynamic-form',
'formFields' => [
'nama',
'deskripsi',
'riwayat',
'file',
],
]); ?>
<div class="container-items"><!-- widgetContainer -->
<?php foreach ($modelsKandidat as $i => $modelsKandidat): ?>
<div class="item panel panel-default"><!-- widgetBody -->
<div class="panel-heading">
<h3 class="panel-title pull-left">Kandidat</h3>
<div class="pull-right">
<button type="button" class="add-item btn btn-success btn-xs"><i class="glyphicon glyphicon-plus"></i></button>
<button type="button" class="remove-item btn btn-danger btn-xs"><i class="glyphicon glyphicon-minus"></i></button>
</div>
<div class="clearfix"></div>
</div>
<div class="panel-body">
<?php
// necessary for update action.
if (! $modelsKandidat->isNewRecord) {
echo Html::activeHiddenInput($modelsKandidat, "[{$i}]id_kandidat");
}
?>
<div class="row">
<div class="col-sm-4">
<?= $form->field($modelsKandidat, "[{$i}]nama")->textInput(['maxlength' => true]) ?>
</div>
<div class="col-sm-4">
<?= $form->field($modelsKandidat, "[{$i}]deskripsi")->textarea(['rows' => 6]) ?>
</div>
<div class="col-sm-4">
<?= $form->field($modelsKandidat, "[{$i}]riwayat")->textarea(['rows' => 6]) ?>
</div>
<div class="col-sm-4">
<?= $form->field($modelsKandidat, "[{$i}]file")->fileInput() ?>
</div>
</div><!-- .row -->
</div>
</div>
<?php endforeach; ?>
</div>
<?php DynamicFormWidget::end(); ?>
</div>
</div>
</div>
<!-- selesai input kandidat !-->
...
<div class="form-group">
<?= Html::submitButton($model->isNewRecord ? 'Create' : 'Update', ['class' => $model->isNewRecord ? 'btn btn-success' : 'btn btn-primary']) ?>
</div>
<?php ActiveForm::end(); ?>
</div>

Answer 1

It's from #shoara/#zahraj answer :
I think you forgot to specify index for your file `
foreach ($modelsKandidat as $keyindex=>$modelKandidat)
{
$modelKandidat->id_election = $model->id_election;
if ($modelKandidat->file = UploadedFile::getInstance($modelKandidat, "[{$keyindex}]file")) {
.......
}
}
see demo controller and form part,imagine $modelCatalogOption in demo is your $model = new Election(); and $modelsOptionValue is your $modelsKandidat = [new Kandidat]; if you try and check your values in your controller I'm sure you can solve this problem easily. Pay attention to actionCreate