Validation for post field title

Just to be a bit more clear - I bought the MB Builder and MB Frontend and did all the setup of meta boxes with its fields there.

Here is the code snipped from the MB Builder Edit Metabox screen:

<?php
add_filter( 'rwmb_meta_boxes', 'your_prefix_register_meta_boxes' );
function your_prefix_register_meta_boxes( $meta_boxes ) {
    $meta_boxes[] = array (
      'id' => 'question',
      'title' => 'Question',
      'pages' =>   array (
         'question',
      ),
      'context' => 'after_title',
      'priority' => 'high',
      'autosave' => false,
      'fields' =>   array (
         
        array (
          'id' => 'post_4',
          'type' => 'post',
          'name' => 'Post',
          'post_type' => 'post',
          'field_type' => 'select_advanced',
        ),
         
        array (
          'id' => 'textarea_bchoa_question_text',
          'type' => 'textarea',
          'name' => 'Question',
          'desc' => 'Please enter any additional content here - be as descriptive as you like.',
          'rows' => '3',
        ),
         
        array (
          'id' => 'checkbox_bchoa_notification',
          'name' => 'Notification',
          'type' => 'checkbox',
          'desc' => 'Check this box if you want to be notified of responses',
          'std' => 1,
        ),
         
        array (
          'id' => 'divider_3',
          'type' => 'divider',
          'name' => 'Divider',
        ),
      ),
    );

    return $meta_boxes;
}

After that, I am using the PHP short code to activate the form as user front end, but I struggle to make the user write into the WP post name field with form validation (and ideally a custom message):

$meta_boxes[] = [
		'id'         => 'question',
		'fields'     => ['title'],
			'validation' => [
				'rules' => [
					'post_title' => [
						'required'   => true,
						'minlength' => 5,
					],
				],
			],
		];
		
	$form = '[mb_frontend_form id="question" post_fields="title" submit_button="Submit Question" confirmation="Thank you for submitting your question, which will be addressed shortly!"]';
	echo do_shortcode( $form );

Please can you send me the correct code? In the future would be nice to have WP fields available in the form builder for MB Frontend and MB Builder.
Thanks
Martin

Hi Anh,

I have done that - copied the php code into functions.php and changed the $form code to what you recommend - but its not working.

What I don't understand I purchased both MB Frontend and MB Builder so why would I need to copy the code - I am under the assumption that both modules do all of that for me without any coding?

The reason why I want to use the post_title is because we are building an FAQ module - so the title should be set by the user entering data (a question) in the front end.

Why could MB Frontend not allow in the visual interface to select post_title and post_excerpt and other WP fields to be selected? Then all this would be just working fine without any additional code?

Pls advise - really need to get this site up and running.

Thanks
Martin

HI Anh,
Just sent you a message through contact form.
Please let me know once you found a solution.
Thanks
Martin