Searchable multiple product select custom field for Woocommerce - php

Question

I am developing a plugin where I need to display some custom select product. So far I can able to make the option field but how can i save them as option field with comma separated product ids like.
45,78,55,48,
here is an example of searchable multiple select option for WooCommerce product.
Here is my code
function crp_select_products() {
global $post, $woocommerce;
$product_ids = array();
?>
<div class="options_group">
<?php if ( $woocommerce->version >= '3.0' ) : ?>
<p class="form-field">
<label for="related_ids"><?php _e( 'Search Products', 'woocommerce' ); ?></label>
<select class="wc-product-search" multiple="multiple" style="width: 50%;" id="related_ids" name="related_ids[]" data-placeholder="<?php esc_attr_e( 'Search for a product…', 'woocommerce' ); ?>" data-action="woocommerce_json_search_products_and_variations">
<?php
foreach ( $product_ids as $product_id ) {
$product = wc_get_product( $product_id );
if ( is_object( $product ) ) {
echo '<option value="' . esc_attr( $product_id ) . '"' . selected( true, true, false ) . '>' . wp_kses_post( $product->get_formatted_name() ) . '</option>';
}
}
?>
</select> <?php echo wc_help_tip( __( 'Select products are for sale product.', 'woocommerce' ) ); ?>
</p>
<?php endif; ?>
</div>
<?php
}

Answer 1

First, there is something missing in your function, to display the saved data in it.
After, this special field need to be displayed inside a form that will have a submit button. So it depends where you are using your function.
Here below is an example displaying that custom field as a custom product setting, save the data and display the saved data in it:
function crp_get_product_related_ids() {
global $post, $woocommerce;
$product_ids = get_post_meta( $post->ID, '_related_ids', true );
if( empty($product_ids) )
$product_ids = array();
?>
<div class="options_group">
<?php if ( $woocommerce->version >= '3.0' ) : ?>
<p class="form-field">
<label for="related_ids"><?php _e( 'Search Products', 'woocommerce' ); ?></label>
<select class="wc-product-search" multiple="multiple" style="width: 50%;" id="related_ids" name="related_ids[]" data-placeholder="<?php esc_attr_e( 'Search for a product…', 'woocommerce' ); ?>" data-action="woocommerce_json_search_products_and_variations">
<?php
foreach ( $product_ids as $product_id ) {
$product = wc_get_product( $product_id );
if ( is_object( $product ) ) {
echo '<option value="' . esc_attr( $product_id ) . '"' . selected( true, true, false ) . '>' . wp_kses_post( $product->get_formatted_name() ) . '</option>';
}
}
?>
</select> <?php echo wc_help_tip( __( 'Select products are for sale product.', 'woocommerce' ) ); ?>
</p>
<?php endif; ?>
</div>
<?php
}
add_action( 'woocommerce_product_options_general_product_data', 'add_custom_fied_in_product_general_fields', 20 );
function add_custom_fied_in_product_general_fields() {
global $post, $woocommerce;
crp_get_product_related_ids();
}
add_action( 'woocommerce_process_product_meta', 'process_product_meta_custom_fied', 20, 1 );
function process_product_meta_custom_fied( $product_id ){
if( isset( $_POST['crosssell_ids'] ) ){
update_post_meta( $product_id, '_related_ids', array_map( 'intval', (array) wp_unslash( $_POST['related_ids'] ) ) );
}
}
Code goes in function.php file of your active child theme (or active theme). Tested and works.