Yii2中DropDownList简单用法示例

<?php
use mon\models\Category;
use yii\helpers\ArrayHelper;
use yii\helpers\Html;
use yii\widgets\ActiveForm;
/ @var $this yii\web\View /
/ @var $model mon\models\Category /
/ @var $form yii\widgets\ActiveForm /
?>
<div class="category-form">
  <div class="row">
    <?php
    if (!$model->isNewRecord) {//如果是编辑分类
      $cate = ArrayHelper::map(Category::find()->andWhere('id != :id', [':id' => $model->id])->all(), 'id', 'title');
    } else {//如果是新建分类
      $cate = ArrayHelper::map(Category::find()->all(), 'id', 'title');
    }
    ?>
    <div class="col-md-6 col-md-offset-3">
      <?php $form = ActiveForm::begin(); ?>
      <?= $form->field($model, 'title')->textInput(['maxlength' => 100])->label("分类标题") ?>
      <?= $form->field($model, 'name')->textInput(['maxlength' => 100])->label("分类别名") ?>
      <?= $form->field($model, 'pid')->dropDownList($cate, ['prompt' => '请选择父分类'])->label("父分类") ?>
      <?= $form->field($model, 'keywords')->textarea(['maxlength' => 255])->label("分类关键词") ?>
      <?= $form->field($model, 'description')->textarea(['maxlength' => 255])->label("分类描述") ?>
      <div class="form-group">
        <div class="row">
          <div class="col-md-6 col-md-offset-3">
            <?= Html::submitButton($model->isNewRecord ? '创建' : '更新', ['class' => $model->isNewRecord ? 'btn btn-block btn-suess' : 'btn btn-block btn-primary']) ?>
          </div>
        </div>
      </div>
      <?php ActiveForm::end(); ?>
    </div>
  </div>
</div>