Display all the subcategories from a specific category?

I need to show all subcategories using

$product_category = wp_get_post_terms( $post->ID, 'product_cat' );

actually I use:

<?php 

global $post;

$terms = get_the_terms( $post->ID, 'product_cat', 'hide_empty=0'  );
foreach ( $terms as $term ){
    $category_id = $term->term_id;
    $category_name = $term->name;
    $category_slug = $term->slug;

    echo '<li><a href="'. get_term_link($term->slug, 'product_cat') .'" rel="nofollow noreferrer noopener">'.$category_name.'</a></li>';
}   

?>

It’s ok but it shows only the parent category and only one subcategory…

How to fix that?

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

Try something like this:

by ID

function woocommerce_subcats_from_parentcat_by_ID($parent_cat_ID) {
    $args = array(
       'hierarchical' => 1,
       'show_option_none' => '',
       'hide_empty' => 0,
       'parent' => $parent_cat_ID,
       'taxonomy' => 'product_cat'
    );
  $subcats = get_categories($args);
    echo '<ul class="wooc_sclist">';
      foreach ($subcats as $sc) {
        $link = get_term_link( $sc->slug, $sc->taxonomy );
          echo '<li><a href="'. $link .'" rel="nofollow noreferrer noopener" rel="nofollow noreferrer noopener">'.$sc->name.'</a></li>';
      }
    echo '</ul>';
}

by NAME

function woocommerce_subcats_from_parentcat_by_NAME($parent_cat_NAME) {
  $IDbyNAME = get_term_by('name', $parent_cat_NAME, 'product_cat');
  $product_cat_ID = $IDbyNAME->term_id;
    $args = array(
       'hierarchical' => 1,
       'show_option_none' => '',
       'hide_empty' => 0,
       'parent' => $product_cat_ID,
       'taxonomy' => 'product_cat'
    );
  $subcats = get_categories($args);
    echo '<ul class="wooc_sclist">';
      foreach ($subcats as $sc) {
        $link = get_term_link( $sc->slug, $sc->taxonomy );
          echo '<li><a href="'. $link .'" rel="nofollow noreferrer noopener" rel="nofollow noreferrer noopener">'.$sc->name.'</a></li>';
      }
    echo '</ul>';
}

Source/inspiration

Edit:

Completed the code, tested it, see comments

Method 2

Here is the code that worked for me in a page template (my parent id was 7):

<?php $wcatTerms = get_terms('product_cat', array('hide_empty' => 0, 'orderby' => 'ASC', 'parent' => 7, )); 
        foreach($wcatTerms as $wcatTerm) : 
        $wthumbnail_id = get_woocommerce_term_meta( $wcatTerm->term_id, 'thumbnail_id', true );
        $wimage = wp_get_attachment_url( $wthumbnail_id );
    ?>
    <div><a href="<?php echo get_term_link( $wcatTerm->slug, $wcatTerm->taxonomy ); ?>" rel="nofollow noreferrer noopener" rel="nofollow noreferrer noopener">
    <?php if($wimage!=""):?><img src="<?php echo $wimage?>" class="aligncenter"><?php endif;?></a>
    <h3 class="text-center"><a href="<?php echo get_term_link( $wcatTerm->slug, $wcatTerm->taxonomy ); ?>" rel="nofollow noreferrer noopener" rel="nofollow noreferrer noopener"><?php echo $wcatTerm->name; ?></a></h3>
    </div>
    <?php endforeach; ?>

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0