您必须手动构建选择HTML
您也可以参考How to give select tag an attribute in cake php?

在cakephp 4中
查找文档
主计长

$countries = $this->Countries->find('all')->where([
            'active' => 1
        ]);

$options = $examples->map(function ($value, $key) {
    return [
        'value' => $value->id,
        'text' => $value->name,
        'data-flag' => $value->iso_code
    ];
});

在视图/模板中

<?= $this->Form->control('country_residence_id', [
                'label' => false,
                'options' => $countries,
                'class' => 'form-control select2-flag-search',
                'data-placeholde' => __('Select Country')
            ]) ?>

看看这个：http://www.dereuromark.de/2012/03/01/some-new-crazy-cakephp-tricks/
“设定某些选取选项的其他属性”

you can try this
    echo $this->Form->input('test', array(
                        'options' => array(
                                            1=>array(
                                            'data-price' => 100, 
                                            'value' => '1', 
                                            'name' => 'My Option'
                                        )),'class' => 'test')
                                    );

您可以这样做：

$options = array(
    ...
    array('name' => 'United states', 'value' => 'USA', 'title' => 'the title that you want', 'class' => 'something'),
    array('name' => 'USA', 'value' => 'USA', 'title' => 'the other title that you want', 'class' => 'otherthing'),
 );

 echo $this->Form->input('test', array('type'=>'select', 'options'=>$options));