YII2之 Scenario

// scenario is set as a property
$model = new User;
$model->scenario = User::SCENARIO_SHOW;

// scenario is set through configuration
$model = new User([‘scenario‘ => User::SCENARIO_SUBMIT]);

<?php


namespace app\models;

use yii\base\Model;

class ContactForm extends Model
{
    public $username;
    public $password;
    public $email;

    const SCENARIO_SHOW = ‘show‘;
    const SCENARIO_SUBMIT = ‘submit‘;

    public function scenarios()
    {
        return [
            self::SCENARIO_SHOW => [‘username‘, ‘password‘],
            self::SCENARIO_SUBMIT => [‘username‘, ‘email‘, ‘password‘],
        ];
    }

    public function rules()
    {
        return [
            // username, email and password are all required in "submit" scenario
            [[‘username‘, ‘email‘, ‘password‘], ‘required‘, ‘on‘ => self::SCENARIO_SUBMIT],

            // username and password are required in "show" scenario
            [[‘username‘, ‘password‘], ‘required‘, ‘on‘ => self::SCENARIO_SHOW],
        ];
    }
    
    public function attributeLabels()
    {

        switch($this->scenario)
        {
            case self::SCENARIO_SHOW:
                $labels = [
                    ‘username‘ => ‘User Name‘,
                    ‘password‘ => ‘Password‘,
                ];
                break;

            case self::SCENARIO_SUBMIT:
                $labels = [
                    ‘username‘ => ‘User Name‘,
                    ‘password‘ => ‘Password‘,
                    ‘email‘ => ‘Your email address‘,
                ];
                break;
        }
        return $labels;
    }
}