There was another issue with the function woocommerce_wp_multi_checkbox() that [I have updated][1] again *(when used in a custom metabox)*.
I have also revisited all your code, specially the last function that saves the multi-checkboxes selected values.
The complete code:
```
// WooCommerce admin custom multi checkbox field function
function woocommerce_wp_multi_checkbox( $field ) {
global $thepostid, $post;
if( ! $thepostid ) {
$thepostid = $post->ID;
}
$field['value'] = get_post_meta( $thepostid, $field['id'], true );
$thepostid = empty( $thepostid ) ? $post->ID : $thepostid;
$field['class'] = isset( $field['class'] ) ? $field['class'] : 'select short';
$field['style'] = isset( $field['style'] ) ? $field['style'] : '';
$field['wrapper_class'] = isset( $field['wrapper_class'] ) ? $field['wrapper_class'] : '';
$field['value'] = isset( $field['value'] ) ? $field['value'] : array();
$field['name'] = isset( $field['name'] ) ? $field['name'] : $field['id'];
$field['desc_tip'] = isset( $field['desc_tip'] ) ? $field['desc_tip'] : false;
echo '<fieldset class="form-field ' . esc_attr( $field['id'] ) . '_field ' . esc_attr( $field['wrapper_class'] ) . '">
<legend>' . wp_kses_post( $field['label'] ) . '</legend>';
if ( ! empty( $field['description'] ) && false !== $field['desc_tip'] ) {
echo wc_help_tip( $field['description'] );
}
echo '<ul class="wc-radios">';
foreach ( $field['options'] as $key => $value ) {
echo '<li><label><input
name="' . esc_attr( $field['name'] ) . '"
value="' . esc_attr( $key ) . '"
type="checkbox"
class="' . esc_attr( $field['class'] ) . '"
style="' . esc_attr( $field['style'] ) . '"
' . ( is_array( $field['value'] ) && in_array( $key, $field['value'] ) ? 'checked="checked"' : '' ) . ' /> ' . esc_html( $value ) . '</label>
</li>';
}
echo '</ul>';
if ( ! empty( $field['description'] ) && false === $field['desc_tip'] ) {
echo '<span class="description">' . wp_kses_post( $field['description'] ) . '</span>';
}
echo '</fieldset>';
}
// Adding a custom Metabox on WooCommerce single orders
add_action( 'add_meta_boxes', 'add_custom_shop_order_metabox' );
function add_custom_shop_order_metabox(){
add_meta_box(
'custom_shop_order_metabox',
__('Employee Extra Actions', 'woocommerce'),
'content_custom_shop_order_metabox',
'shop_order',
'side',
'core'
);
}
// Custom Metabox content on WooCommerce single orders
function content_custom_shop_order_metabox() {
global $thepostid, $post;
echo '<div class="options_group">';
woocommerce_wp_multi_checkbox( array(
'id' => 'employee_actions12',
'name' => 'employee_actions12[]',
'label' => __('Levels', 'woocommerce'),
'options' => array(
'tee' => __( 'MBO', 'woocommerce' ),
'saa' => __( 'HBO', 'woocommerce' ),
'tee1' => __( 'WO', 'woocommerce' ),
),
) );
echo '</div>';
}
// Save WooCommerce single orders Custom Metabox field values
add_action( 'save_post_shop_order', 'save_custom_shop_order_metabox_field_values' );
function save_custom_shop_order_metabox_field_values( $post_id ){
if ( ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE )
|| ! current_user_can( 'edit_shop_order', $post_id ) ) {
return;
}
if( isset( $_POST['employee_actions12'] ) ){
update_post_meta( $post_id, 'employee_actions12', wc_clean($_POST['employee_actions12']) );
}
}
```
Code goes in functions.php file of the active child theme (or active theme). Tested and works.
[1]: https://stackoverflow.com/questions/50799927/multi-checkbox-fields-in-woocommerce-backend/50802095#50802095
**2021 Update**
> **2021 Update** - Solved issues with: <br>
• `in_array()` where 2nd argument was a string on start*. <br>
• `$thepostid` as in some cases it was empty.
That is possible creating a custom function this way:
// New Multi Checkbox field for woocommerce backend
function woocommerce_wp_multi_checkbox( $field ) {
global $thepostid, $post;
if( ! $thepostid ) {
$thepostid = $post->ID;
}
$field['value'] = get_post_meta( $thepostid, $field['id'], true );
$thepostid = empty( $thepostid ) ? $post->ID : $thepostid;
$field['class'] = isset( $field['class'] ) ? $field['class'] : 'select short';
$field['style'] = isset( $field['style'] ) ? $field['style'] : '';
$field['wrapper_class'] = isset( $field['wrapper_class'] ) ? $field['wrapper_class'] : '';
$field['value'] = isset( $field['value'] ) ? $field['value'] : array();
$field['name'] = isset( $field['name'] ) ? $field['name'] : $field['id'];
$field['desc_tip'] = isset( $field['desc_tip'] ) ? $field['desc_tip'] : false;
echo '<fieldset class="form-field ' . esc_attr( $field['id'] ) . '_field ' . esc_attr( $field['wrapper_class'] ) . '">
<legend>' . wp_kses_post( $field['label'] ) . '</legend>';
if ( ! empty( $field['description'] ) && false !== $field['desc_tip'] ) {
echo wc_help_tip( $field['description'] );
}
echo '<ul class="wc-radios">';
foreach ( $field['options'] as $key => $value ) {
echo '<li><label><input
name="' . esc_attr( $field['name'] ) . '"
value="' . esc_attr( $key ) . '"
type="checkbox"
class="' . esc_attr( $field['class'] ) . '"
style="' . esc_attr( $field['style'] ) . '"
' . ( is_array( $field['value'] ) && in_array( $key, $field['value'] ) ? 'checked="checked"' : '' ) . ' /> ' . esc_html( $value ) . '</label>
</li>';
}
echo '</ul>';
if ( ! empty( $field['description'] ) && false === $field['desc_tip'] ) {
echo '<span class="description">' . wp_kses_post( $field['description'] ) . '</span>';
}
echo '</fieldset>';
}
Code goes in function.php file of your active child theme (or active theme). Tested and works.
> Related: https://stackoverflow.com/questions/50132928/multi-select-fields-in-woocommerce-backend/50159063#50159063
------
Usage example *(for a simple product)*:
// Add custom multi-checkbox field for product general option settings
add_action( 'woocommerce_product_options_general_product_data', 'add_custom_settings_fields', 20 );
function add_custom_settings_fields() {
global $post;
echo '<div class="options_group hide_if_variable"">'; // Hidding in variable products
woocommerce_wp_multi_checkbox( array(
'id' => '_custom_level',
'name' => '_custom_level[]',
'label' => __('Levels', 'woocommerce'),
'options' => array(
'MBO' => __( 'MBO', 'woocommerce' ),
'HBO' => __( 'HBO', 'woocommerce' ),
'WO' => __( 'WO', 'woocommerce' )
)
) );
echo '</div>';
}
// Save custom multi-checkbox fields to database when submitted in Backend (for all other product types)
add_action( 'woocommerce_process_product_meta', 'save_product_options_custom_fields', 30, 1 );
function save_product_options_custom_fields( $post_id ){
if( isset( $_POST['_custom_level'] ) ){
$post_data = $_POST['_custom_level'];
// Data sanitization
$sanitize_data = array();
if( is_array($post_data) && sizeof($post_data) > 0 ){
foreach( $post_data as $value ){
$sanitize_data[] = esc_attr( $value );
}
}
update_post_meta( $post_id, '_custom_level', $sanitize_data );
}
}
Code goes in function.php file of your active child theme (or active theme). Tested and works.
[![enter image description here][1]][1]
> The selected values are correctly saved and displayed. For info the value is an array.
[1]: https://i.stack.imgur.com/F3ua9.png
