该方法有两个步骤：第一，一个用于保存自定义metabox字段数据的函数（钩住以保存\\u post），第二，一个用于读取新post\\u meta（刚刚保存）、验证它并根据需要修改保存结果的函数（也钩住以保存\\u post，但在第一个之后）。如果验证失败，validator函数实际上会将post\\u状态改回“挂起”，从而有效阻止发布帖子。

由于save\\u post函数被多次调用，因此每个函数都有检查，仅在用户想要发布时执行，并且仅针对您的自定义post类型（mycustomtype）。

我通常还会添加一些自定义的通知消息，以帮助用户了解他们的帖子没有发布的原因，但这些消息在这里包含起来有点复杂。。。

我还没有测试过这段精确的代码，但它是我在大规模自定义帖子类型设置中所做工作的简化版本

add_action(\'save_post\', \'save_my_fields\', 10, 2);
add_action(\'save_post\', \'completion_validator\', 20, 2);

function save_my_fields($pid, $post) {
    // don\'t do on autosave or when new posts are first created
    if ( ( defined( \'DOING_AUTOSAVE\' ) && DOING_AUTOSAVE ) || $post->post_status == \'auto-draft\' ) return $pid;
    // abort if not my custom type
    if ( $post->post_type != \'mycustomtype\' ) return $pid;

    // save post_meta with contents of custom field
    update_post_meta($pid, \'mymetafield\', $_POST[\'mymetafield\']);
}


function completion_validator($pid, $post) {
    // don\'t do on autosave or when new posts are first created
    if ( ( defined( \'DOING_AUTOSAVE\' ) && DOING_AUTOSAVE ) || $post->post_status == \'auto-draft\' ) return $pid;
    // abort if not my custom type
    if ( $post->post_type != \'mycustomtype\' ) return $pid;

    // init completion marker (add more as needed)
    $meta_missing = false;

    // retrieve meta to be validated
    $mymeta = get_post_meta( $pid, \'mymetafield\', true );
    // just checking it\'s not empty - you could do other tests...
    if ( empty( $mymeta ) ) {
        $meta_missing = true;
    }

    // on attempting to publish - check for completion and intervene if necessary
    if ( ( isset( $_POST[\'publish\'] ) || isset( $_POST[\'save\'] ) ) && $_POST[\'post_status\'] == \'publish\' ) {
        //  don\'t allow publishing while any of these are incomplete
        if ( $meta_missing ) {
            global $wpdb;
            $wpdb->update( $wpdb->posts, array( \'post_status\' => \'pending\' ), array( \'ID\' => $pid ) );
            // filter the query URL to change the published message
            add_filter( \'redirect_post_location\', create_function( \'$location\',\'return add_query_arg("message", "4", $location);\' ) );
        }
    }
}

您必须在ajax上检查/验证您的元字段值，即当用户点击“发布/更新”按钮时。在这里，我正在验证woocommerce产品的元字段“product\\u number”是否为空值。

add_action(\'admin_head-post.php\',\'ep_publish_admin_hook\');
add_action(\'admin_head-post-new.php\',\'ep_publish_admin_hook\');

function ep_publish_admin_hook(){
    global $post;
    if ( is_admin() && $post->post_type == \'product\' ){
        ?>
        <script language="javascript" type="text/javascript">
            (function($){
                jQuery(document).ready(function() {

                    jQuery(\'#publish\').click(function() {
                        if(jQuery(this).data("valid")) {
                            return true;
                        }

                        //hide loading icon, return Publish button to normal
                        jQuery(\'#publishing-action .spinner\').addClass(\'is-active\');
                        jQuery(\'#publish\').addClass(\'button-primary-disabled\');
                        jQuery(\'#save-post\').addClass(\'button-disabled\');

                        var data = {
                            action: \'ep_pre_product_submit\',
                            security: \'<?php echo wp_create_nonce( "pre_publish_validation" ); ?>\',
                            \'product_number\': jQuery(\'#acf-field-product_number\').val()
                        };
                        jQuery.post(ajaxurl, data, function(response) {

                            jQuery(\'#publishing-action .spinner\').removeClass(\'is-active\');
                            if ( response.success ){
                                jQuery("#post").data("valid", true).submit();
                            } else {
                                alert("Error: " + response.data.message );
                                jQuery("#post").data( "valid", false );

                            }
                            //hide loading icon, return Publish button to normal
                            jQuery(\'#publish\').removeClass(\'button-primary-disabled\');
                            jQuery(\'#save-post\').removeClass(\'button-disabled\');
                        });
                        return false;
                    });
                });
            })(jQuery);
        </script>
        <?php
    }
}

add_action(\'wp_ajax_ep_pre_product_submit\', \'ep_pre_product_submit_func\');
function ep_pre_product_submit_func() {
    //simple Security check
    check_ajax_referer( \'pre_publish_validation\', \'security\' );

    if ( empty( $_POST[\'product_number\'] ) || empty( $_POST[\'file_attachment\'] ) ) {
         $data = array(
            \'message\' => __(\'Please enter part number and specification document.\'),
        );
        wp_send_json_error( $data );
    }
    wp_send_json_success();
}

只是想添加它来读取post变量，使用Bainternet的解决方案，您必须在$_POST[\'form_data\'] 使用PHPparse_str 功能（只是为了节省您一些研究时间）。

$vars = parse_str( $_POST[\'form_data\'] );

$vars = parse_str ( $_POST[\'form_data\'] ) 
if ( $my_meta == "something" ) { // do something }