Custom shortcode is not working in text widget

Question

I have created function for creating shortcode in function.php. This function looks like below

function related_category_sidebar() {
    include_once(WP_PLUGIN_DIR.'/sabai-directory/assets/templates/template_related_category.php');
}
add_shortcode( 'related_category', 'related_category_sidebar' );

Now, I have created custom widget sidebar like :

add_action( 'widgets_init', 'theme_slug_widgets_init' );
function theme_slug_widgets_init() {
    register_sidebar( array(
         'name' => __( 'Related Category', 'theme-slug' ),
         'id' => 'rel_cat',
         'description' => __( 'Widgets in this area will be shown on all posts and pages.', 'theme-slug' ),
         'before_widget' => '<li id="%1$s" class="widget %2$s">',
         'after_widget'  => '</li>',
         'before_title'  => '<h2 class="widgettitle">',
         'after_title'   => '</h2>',
     ) );
}

Now, I have add text widget in this Related category widget area. Then after I have called widget area in custom file as :

<?php dynamic_sidebar('rel_cat'); ?>

But shorcode is not working. Here, I have used <?php echo do_shortcode('[related_category]'); ?> direct in file so its working.

But, I want to use shortcode using widget area so what should I have to change in my code?

Answer 1

Shortcodes need to return data, not echo it - use output buffering to capture the output of the include and return it:

function related_category_sidebar() {
    ob_start();
    include WP_PLUGIN_DIR . '/sabai-directory/assets/templates/template_related_category.php';
    return ob_get_clean();
}

Then you will also need to do as Charles suggested and enable shortcodes for text widgets:

add_filter( 'widget_text', 'do_shortcode', 11 );