How to list all posts (if any) in a select list when any post type selected from other select list

Question

I got success in getting all post types in a select Select Post Type

<select name="meta-select" id="select_post_types" class="form-control">  
    <?php foreach ( $post_types as $post_type ) { ?>
    <option value="<?php print $post_type; ?>"> <?php print $post_type; ?> </option>
    <?php } ?>
</select>

but I want to populate the posts of all selected post type when admin select from the top select.

Second select is followed

<select name="meta-select" id="select_post" class="form-control">  
    <option value=""> </option>';

</select>

Answer 1

<?php
$args = array(
   'public'   => true,
   '_builtin' => false
);

$output = 'names'; // names or objects, note names is the default
$operator = 'and'; // 'and' or 'or'

$post_types = get_post_types( $args, $output, $operator ); 
?>
<select name="meta-select" id="select_post" class="form-control">  
    <?php
    foreach ( $post_types  as $post_type ) {

       ?>
       <option value="<?php print $post_type; ?>"> <?php print $post_type; ?> </option>

       <?php
    }

    ?>
</select>