一、目录结构：

模型类：models/

视图文件：views/

二、MVC示例：

在controllers下的SiteController.php里新增方法：

//action后面的操作映射为say-hello
    public function actionSayHello($message='World'){
        return $this->render('say',['message'=>$message]);
    }

在views/site下新建视图say.php，内容：

<?php
use yii\helpers\Html;
?>
<?=Html::encode($message)?>

输入网址：http://test.com/index.php?r=site/say-hello&message=OK 

查看输出结果

三、Form示例

修改SiteControlloer.php：

<?php

namespace app\controllers;

use Yii;
use yii\filters\AccessControl;
use yii\web\Controller;
use yii\filters\VerbFilter;
use app\models\LoginForm;
use app\models\ContactForm;
use app\models\EntryForm;

class SiteController extends Controller
{
    public function behaviors()
    {
        return [
            'access' => [
                'class' => AccessControl::className(),
                'only' => ['logout'],
                'rules' => [
                    [
                        'actions' => ['logout'],
                        'allow' => true,
                        'roles' => ['@'],
                    ],
                ],
            ],
            'verbs' => [
                'class' => VerbFilter::className(),
                'actions' => [
                    'logout' => ['post'],
                ],
            ],
        ];
    }

    public function actions()
    {
        return [
            'error' => [
                'class' => 'yii\web\ErrorAction',
            ],
            'captcha' => [
                'class' => 'yii\captcha\CaptchaAction',
                'fixedVerifyCode' => YII_ENV_TEST ? 'testme' : null,
            ],
        ];
    }

    public function actionIndex()
    {
        return $this->render('index');
    }

    public function actionLogin()
    {
        if (!\Yii::$app->user->isGuest) {
            return $this->goHome();
        }

        $model = new LoginForm();
        if ($model->load(Yii::$app->request->post()) && $model->login()) {
            return $this->goBack();
        } else {
            return $this->render('login', [
                'model' => $model,
            ]);
        }
    }

    public function actionLogout()
    {
        Yii::$app->user->logout();

        return $this->goHome();
    }

    public function actionContact()
    {
        $model = new ContactForm();
        if ($model->load(Yii::$app->request->post()) && $model->contact(Yii::$app->params['adminEmail'])) {
            Yii::$app->session->setFlash('contactFormSubmitted');

            return $this->refresh();
        } else {
            return $this->render('contact', [
                'model' => $model,
            ]);
        }
    }

    public function actionAbout()
    {
        return $this->render('about');
    }

    //action后面的操作映射为say-hello
    public function actionSayHello($message='World'){
        return $this->render('say',['message'=>$message]);
    }
    public function actionEntry(){
        $model=new EntryForm;
        if($model->load(Yii::$app->request->post()) && $model->validate()){
            return $this->render('entry-confirm',['model'=>$model]);
        }else
        {
            return $this->render('entry',['model'=>$model]);
        }
    }
}

新增ModelEntryForm.php：

<?php
namespace app\models;
use yii\base\Model;

class EntryForm extends Model{
  public $name;
  public $email;
  
  public function rules()
  {
    return [
        [['name','email'],'required'],
        ['email','email']
        
    ];
  }
}

新增视图entry.php：

<?php 
use yii\helpers\Html;
use yii\widgets\ActiveForm;
?>

<?php 
$form=ActiveForm::begin();
?>
<?= $form->field($model,'name')?>
<?= $form->field($model,'email')?>

<div class="form-group">
  <?=Html::submitButton('Submit',['class'=>'btn btn-primary'])?>
</div>

<?php ActiveForm::end();?>

新增视图entry-confirm.php：

<?php
use yii\helpers\Html;
?>
<p>
You have entered the following information:</p>

<ul>
<li><label>Name</label>:<?= Html::encode($model->name)?>
</li>
<li><label>Email</label>:<?=Html::encode($model->email)?>
</ul>

现在目录结构是这样的：

测试：http://test.com/index.php?r=site/entry