Yii Framework 2.0规则日期验证器

I am using Yii Framework 2.0. I have a form with a text input field which is meant for a date. I have read the Yii Framework 2.0 about the Class yii\validators\Validator and known all the validator keys which can be used inside of the rules() method in a model class. When I use the date key as below, it does not validate anything. It means that I still can put some text in that input field and can post the form.

When I changed it into boolean or email, I could see that it validates very well when I put something wrong in the input field. How can I validate a date value inside of an input field with Yii Framework 2.0?

My rules() method:

public function rules()
{
    return [
         [['inputfield_date'], 'required'],
         [['inputfield_date'], 'safe'],
         [['inputfield_date'], 'date'],
    ];
}

My view page:

<?php $form = ActiveForm::begin(); ?>
     <?= $form->field($model, 'inputfield_date')->textInput(); ?>
<?php ActiveForm::end(); ?>

Not 100% sure how it is in Yii2, but going out from Yii1 that had to look like this...

array('org_datetime', 'date', 'format'=>'yyyy-M-d H:m:s'),

(source: http://www.yiiframework.com/wiki/56/#hh8)

...I'd say i'd have to look something like this in Yii2:

['shopping_date', 'date', 'format' => 'yyyy-M-d H:m:s'],

Working solution. My rules() method:

public function rules()
{
   return [
     [['inputfield_date'], 'required'],
     [['inputfield_date'], 'safe'],
     ['inputfield_date', 'date', 'format' => 'yyyy-M-d H:m:s'],
   ];
}

My form in the view page:

<?php $form = ActiveForm::begin(); ?>
   <?= $form->field($model, 'inputfield_date')->textInput(); ?>
<?php ActiveForm::end(); ?>

My method in controller:

if ($model->load(Yii::$app->request->post()) && $model->validate()):
        if($model->save()):
            // some other code here.....
        endif;
endif;

Note that the date format depends on how you define your date format input field. Note once again that this is not an AJAX validator. After clicking on the submit button, you will see the error message if you enter something else which is not a date.

Boy the Yii docs suck. They don't even give an example. Working from O'Connor's answer, this worked for me since I was assigning the value in 2015-09-11 format.

// Rule
[['event_date'], 'date', 'format' => 'php:Y-m-d']
// Assignment
$agkn->event_date = date('Y-m-d');

The docs don't even specify where format or timestampAttribute came from, or how to use them. It doesn't even say what the heck from_date and to_date are. And most of all, no examples!

You can validate for date like this from model rules

public function rules(){
    return [
        [['date_var'],'date', 'format'=>'d-m-yy'],
        [['from_date', 'to_date'], 'default', 'value' => null],
        [['from_date', 'to_date'], 'date'],
    ];
}