使用语言和项目编号Yii2验证输入

Question

I have form with dynamic field and input like this

$form->field($model_dt, "[{$lang['id']}][{$i}]title")->textInput()

$lang['id'] represent language id and $i number of appended row. How can I validate input like this?

<?php foreach (\common\models\Language::find()->all() as $lang) : ?>
            <div class="container-items row justify-content-center mt-4 pt-4" id="slides-body-<?= $lang['id'] ?>">
                <?php foreach ($model_data[$lang['id']] as $i => $model_dt): ?>
                <div class="item panel panel-default col-lg-10 p-0 mt-2 align-self-center"><!-- widgetBody -->
                    <div class="panel-heading">
                        <h3 class="panel-title pull-left">Slide data #<?= $i.'-'.$lang['name'] ?></h3>
                        <div class="pull-right">
                            <button type="button" lang="<?= $lang['id'] ?>" 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">
                        <div class="row">
                            <div class="col-lg-3">
                                <img src="<?= isset($model_dt[$lang['id']]) ? $model_dt[$lang['id']][$i]['name'] : '' ?>" style="max-width: 207px;" id="thumb-slides-<?= $lang['id'] ?>-<?= $i ?>-image">
                                <?= $form->field($model_dt, "[{$lang['id']}][{$i}]image")->widget(\mihaildev\elfinder\InputFile::className()) ?>
                            </div>
                            <div class="col-lg-3">
                                <?= $form->field($model_dt, "[{$lang['id']}][{$i}]title")->textInput() ?>
                            </div>
                            <div class="col-lg-3">
                                <?= $form->field($model_dt, "[{$lang['id']}][{$i}]desc")->textarea(['rows' => 3]) ?>
                            </div>
                            <div class="col-lg-3">
                                <?= $form->field($model_dt, "[{$lang['id']}][{$i}]button")->textInput() ?>
                            </div>
                        </div>
                    </div>
                </div>
                <?php $i++ ?>
                <?php endforeach;?>
            </div>
                <?php endforeach; ?>