Yii2中DropDownList简单用法示例

<?phpuse common/models/Category;use yii/helpers/ArrayHelper;use yii/helpers/Html;use yii/widgets/ActiveForm;/* @var $this yii/web/View *//* @var $model common/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-success' : 'btn btn-block btn-primary']) ?>          </div>        </div>      </div>      <?php ActiveForm::end(); ?>    </div>  </div></div>