我正在使用CMB2和CMB2帖子搜索字段在不同类型的帖子（包括自定义帖子类型）之间创建一对多链接，帖子搜索字段位于可重复的元框组中，以便每个连接的帖子都有一些文本来提供连接的上下文。我已经让它正常工作了-除非一个帖子没有任何连接的帖子。如果字段/组为空，我的帖子/页面模板将重复主要帖子内容，而不是预期的连接帖子。

设置我的metabox：

function gwl_register_post_connection_metabox() {
$prefix = \'gwl_collection_post_connection_\';

$cmb_group = new_cmb2_box( array(
    \'id\'           => $prefix . \'metabox\',
    \'title\'        => __( \'Connected posts\', \'gwl-cd\' ),
    \'object_types\' => array( \'post\',\'page\',\'gwl_exhibition\' ), 
) );

$group_field_id = $cmb_group->add_field( array(
    \'id\'          => $prefix . \'group\',
    \'type\'        => \'group\',
    \'description\' => __( \'You can connect different collection items and names, as well as posts and other content from across the website.\', \'gwl-cd\' ),
    \'options\'     => array(
        \'group_title\'   => __( \'Connected post {#}\', \'gwl-cd\' ), 
        \'add_button\'    => __( \'Add another post\', \'gwl-cd\' ),
        \'remove_button\' => __( \'Remove post\', \'gwl-cd\' ),
        \'sortable\'      => true, 
    ),
) );

$cmb_group->add_group_field( $group_field_id, array(
    \'name\'        => __( \'Connected Post\', \'gwl-cd\' ),
    \'description\' => __( \'Select an item, name or post by entering the post ID, or click on the search symbol to find a post\', \'gwl-cd\' ),
    \'id\'          => $prefix . \'related_post\',
    \'type\'        => \'post_search_text\', 
    \'post_type\'   => array( \'post\',\'page\',\'gwl_exhibition\',\'gwl_name\',\'gwl_item\' ), 
    \'select_type\' => \'radio\',
    \'select_behavior\' => \'replace\',
) );

$cmb_group->add_group_field( $group_field_id, array(
    \'name\'        => __( \'Context\', \'gwl-cd\' ),
    \'description\' => __( \'How does this collection item or other post relate to the main article?\', \'gwl-cd\' ),
    \'id\'          => $prefix . \'context\',
    \'type\'    => \'wysiwyg\',
    \'options\' => array(
        \'media_buttons\' => false, // hide insert/upload button(s) << TBD
        \'textarea_rows\' => get_option(\'default_post_edit_rows\', 6), 
    ),
) );

}

function gwl_output_connections( $gwl_collection_post_connection_group ) {

$connections = get_post_meta( get_the_ID(), \'gwl_collection_post_connection_group\', true );

if ( ! empty( $connections ) ) {

    foreach ( (array) $connections as $key => $connection ) {

        $relpost = $desc = \'\';

        if ( isset( $connection[\'gwl_collection_post_connection_related_post\'] ) ) 
            $relpost = esc_html( $connection[\'gwl_collection_post_connection_related_post\'] );

        if ( isset( $connection[\'gwl_collection_post_connection_context\'] ) )
            $desc = wpautop( $connection[\'gwl_collection_post_connection_context\'] );

        echo \'<div class="connected-post"><h3><a href="\';
        echo get_permalink( $relpost );
        echo \'">\';
        echo get_the_title( $relpost );
        echo \'</a></h3> <p>\';
        echo get_the_excerpt( $relpost );
        echo \'</p><p>\';
        echo $desc;
        echo \'</p></div>\';
    }
}

else {
    echo \'<p>There are no connected posts.</p>\';
}

}