yii2: make checkbox to be checked

Question

I am using Yii2 framework and I'd like to generate an html code like this

<input type="checkbox" id="queue-order" name="Queue[order]" value="1" checked>

in a view which uses ActiveForm.

I've tried

echo $form->field($model, 'order')
          ->checkBox(['label' => ..., 'uncheck' => null, 'checked' => true]); 

as well as

echo $form->field($model, 'order')
          ->checkBox(['label' => ..., 'uncheck' => null, 'checked' => 'checked']); 

but desired string "checked" does not appear in the generated html code.

Strangely enough, if I substitute "checked" with "selected"

echo $form->field($model, 'order')
          ->checkBox(['label' => ..., 'uncheck' => null, 'selected' => true]); 

then generated html code contains attribute "selected":

<input type="checkbox" id="queue-order" name="Queue[order]" value="1" selected>

So, how can I generate html code for a checkbox with attribute "checked"?

Answer 1

I guess this checkbox will be checked only if $model->order property take true value and if it has false (0 or null or false etc) value - field will be unchecked.