Yii2 怎么动态设置验证规则？

Question

比如像这样：

$model = new \yii\base\Model();

// 怎么动态设置验证规则，动态生成表单
$model->rule = [
    // 验证规则
];

$model->load(Yii::$app->request->post());
$model->validate();

Answer 1

$model = new \yii\base\DynamicModel(['username', 'sex']);
$model->addRule(['username', 'sex'], 'required');
$model->addRule('username', 'string', ['min' => 4]);

$model->load(['username' => 'xy'], '');
$model->validate();

var_dump($model->errors);