Yii2 DropDownList Simple Usage Example _php instance

The examples in this paper describe the simple usage of DropDownList in YII2. Share to everyone for your reference, as follows:

Here, the practical application is used as an example to explain Yii2 DropDownList usage.

There is a classification table, infinite pole classification of the kind, table structure as follows, PID is the parent category ID
Here we want to achieve:

When creating a new category, the parent category can be selected from any of the categories or not selected

When editing a category, the parent category cannot select the currently edited category ... If you choose yourself, the parent category is your own, must be wrong!

The implementation code is as follows, I'll put all the code of the form

<?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 */?> <?ph P if (! $model->isnewrecord) {//If it is an edit category $cate = Arrayhelper::map (Category::find ()->andwhere (' id! =: id ', [': I    d ' = $model->id])->all (), ' id ', ' title ');    } else {//If it is a new classification $cate = Arrayhelper::map (Category::find ()->all (), ' id ', ' title '); }?> <?php $form = Activeform::begin ()?> <?= $form->field ($model, ' title ')->textinput ([' maxlength ' = +])->label ("category title")?> <?= $form->field ($model, ' name ')->textinput ([' maxlength ' = >])->label ("classification alias")?> <?= $form->field ($model, ' pid ')->dropdownlist ($cate, [' prompt ' = ' = ' Please select Parent category '])->label ("parent category")?> <?= $form->field ($model, ' keywords ')->textarea ([' maxlength ' = = 255])->l Abel("categorical keywords")?> <?= $form->field ($model, ' description ')->textarea ([' maxlength ' = = 255])->label ("Category description" )?> <?= Html::submitbutton ($model->isnewrecord? ' Create ': ' Update ', [' class ' = $model->isnewrecord?  ' Btn btn-block btn-success ': ' btn btn-block btn-primary ']?> <?php activeform::end ();       ?>

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It is hoped that this article is helpful to the PHP program design based on YII framework.

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