Dependency in admin form field in magento 2

Question

How to set dependency of admin form field in magento 2?

How can i set dependency of admin fields

I am trying this code

$this->setChild('form_after',
        $this->getLayout()->createBlock('Magento\Backend\Block\Widget\Form\Element\Dependence')
            ->addFieldMap('answers', 'answer')
            ->addFieldMap('is_status', 'status')
            ->addFieldDependence('status', 'answer', 'Customer')

    );

but its not working

EDIT

protected function _prepareForm()
{
    ......
    $model = $this->_coreRegistry->registry('answers');
    $form = $this->_formFactory->create();
    $form->setHtmlIdPrefix('page_');

     $fieldset = $form->addFieldset('base_fieldset', ['legend' => __('Answer Information')]);
    if ($model->getId()) {
        $fieldset->addField('answers_id', 'hidden', ['name' => 'answers_id']);
    }

    $fieldset->addField(
        'answers',
        'select',
        [
            'label' => __('Answer'),
            'title' => __('Answer'),
            'name' => 'answers',
            options => $this->_answerby->getOptionArray(),
        ]

    ); 
    $fieldset->addField(
        'is_status',
        'text',
        [
           'label' => __('Status'),
            'title' => __('Status'),
            'name' => 'is_status',
        ]

    ); 

    $this->setChild('form_after',
    $this->getLayout()->createBlock('Magento\Backend\Block\Widget\Form\Element\Dependence')
        ->addFieldMap('answers', 'answer')
        ->addFieldMap('is_status', 'status')
        ->addFieldDependence('status', 'answer', 'Customer')

);
     $form->setValues($model->getData());

    $this->setForm($form);

    return parent::_prepareForm();
}

 

Answer 1

You should add this in your form.

protected function _prepareForm()
{
    ......
    $model = $this->_coreRegistry->registry('some_registry');
    $form = $this->_formFactory->create();
    $form->setHtmlIdPrefix('page_');
    $htmlIdPrefix = $form->getHtmlIdPrefix();
    $fieldset->addField(
        'answers',
        'select',
        [
            .....
        ],
        'to'
    ); 
    $fieldset->addField(
        'is_status',
        'text',
        [
           .....
            'display' => 'none'
        ],
        'answers'
    ); 
    // write this before  this line $this->setForm($form);
    $this->setChild(
        'form_after',
        $this->getLayout()->createBlock(
            'Magento\Backend\Block\Widget\Form\Element\Dependence'
        )->addFieldMap(
            "{$htmlIdPrefix}answers",
            'answers'
        )
        ->addFieldMap(
            "{$htmlIdPrefix}is_status",
            'is_status'
        )
        ->addFieldDependence(
            'is_status',
            'answers',
            'Customer'
        )
    );
    .....
}

This code works.