Displaying custom field of product variations within Woocommerce orders and emails

Question

I successfully added a custom field for product variations within the backend of WooCommerce and was able to display its value. I'd like to contain this value within order and emails as well.

//Display Fields in admin on product edit screen
add_action( 'woocommerce_product_after_variable_attributes', 'woo_variable_fields', 10, 3 );

//Save variation fields values
add_action( 'woocommerce_save_product_variation', 'save_variation_fields', 10, 2 );

// Create new fields for variations
function woo_variable_fields( $loop, $variation_data, $variation ) {

echo '<div class="variation-custom-fields">';

  // Text Field
  woocommerce_wp_text_input( 
    array( 
      'id'          => '_text_field['. $loop .']', 
      'label'       => __( 'additional fees (e.g. monthly fee)', 'woocommerce' ), 
      'placeholder' => '',
      //'desc_tip'    => true,
      'wrapper_class' => 'form-row form-row-first',
      //'description' => __( 'Enter the custom value here.', 'woocommerce' ),
      'value'       => get_post_meta($variation->ID, '_text_field', true)
    )
  );

echo "</div>"; 

}

/** Save new fields for variations */
function save_variation_fields( $variation_id, $i) {

// Text Field
$text_field = stripslashes( $_POST['_text_field'][$i] );
update_post_meta( $variation_id, '_text_field', esc_attr( $text_field ) );
}

// Custom Product Variation
add_filter( 'woocommerce_available_variation', 'custom_load_variation_settings_products_fields' );

function custom_load_variation_settings_products_fields( $variations )    { 
$variations['variation_custom_field'] = get_post_meta( $variations[ 'variation_id' ], '_text_field', true );  
return $variations;
}

I'm using the following to display the custom field's value within the cart.

add_filter( 'woocommerce_get_item_data', 'display_custom_field_as_item_data', 20, 2 );
function display_custom_field_as_item_data( $cart_data, $cart_item ) {
    if( $value = get_post_meta( $cart_item['data']->get_id(), '_text_field', true ) ){
        $cart_data[] = array(
            'name' => __( 'Additional Monthly Fee', 'woocommerce' ),
            'value' => sanitize_text_field( $value )
        );
    }
    return $cart_data;
}

Further as for now I'm displaying its value below the product price / total of each item within cart/checkout template with the following

echo get_post_meta( $_product->get_id(), '_text_field', true );

How about displaying the value of this field within orders and emails?

Answer 1

Updated: To display that in order pages and email notifications try the following additional functions (I have made some changes in the woocommerce_get_item_data hooked function, so you need to replace it with the following one) :

// Save custom field value in cart item
add_filter( 'woocommerce_add_cart_item_data', 'save_custom_field_in_cart_object', 30, 3 );
function save_custom_field_in_cart_object( $cart_item_data, $product_id, $variation_id ) {

    // Get the correct Id to be used
    $the_id = $variation_id > 0 ? $variation_id : $product_id;

    if( $value = get_post_meta( $the_id, '_text_field', true ) )
        $cart_item_data['custom_data'] = sanitize_text_field( $value );

    return $cart_item_data;
}

// Display on cart and checkout pages
add_filter( 'woocommerce_get_item_data', 'display_custom_field_as_item_data', 20, 2 );
function display_custom_field_as_item_data( $cart_data, $cart_item ) {
    if( isset( $cart_item['custom_data'] ) ){
        $cart_data[] = array(
            'name' => __( 'Additional Monthly Fee', 'woocommerce' ),
            'value' => $cart_item['custom_data']
        );
    }
    return $cart_data;
}

// Save custom field value in order items meta data
add_action( 'woocommerce_add_order_item_meta', 'add_custom_field_to_order_item_meta', 20, 3 );
function add_custom_field_to_order_item_meta( $item_id, $values, $cart_item_key ) {

    if( isset( $values['custom_data'] ) )
        wc_add_order_item_meta( $item_id, __( 'Additional Monthly Fee', 'woocommerce' ), $values['custom_data'] );
}

Code goes in function.php file of your active child theme (or theme). Tested and works.

It will display the custom field label and value in all Order pages and in email notifications too.