最后，我发现我无法绑定或触发此操作。我必须用javascript和ajax回调复制它，如下所示。

Javascript:

function PrismSetAsThumbnail(id, nonce){  
    var $link = jQuery(\'a#wp-post-thumbnail-\' + id);

    $link.text( setPostThumbnailL10n.saving );
    jQuery.post(ajaxurl, {
        action:"prism_set_thumbnail", post_id: post_id, thumbnail_id: id, _ajax_nonce: nonce, cookie: encodeURIComponent(document.cookie)
    }, function(str){
        var win = window.dialogArguments || opener || parent || top;  
        $link.text( setPostThumbnailL10n.setThumbnail );
        if ( str == \'0\' ) {
            alert( setPostThumbnailL10n.error );
        } else {
            jQuery(\'a.wp-post-thumbnail\').show();
            $link.text( setPostThumbnailL10n.done );
            $link.fadeOut( 2000 );

            //display new thumbnail in the columns w/o refresh
            jQuery(\'#post-\'+win.post_id + \' .postimagediv a\', win.parent.document).html(str).fadeIn();

            //if successful close thickbox
            win.parent.tb_remove();
        } 
    }
    );
}

Ajax Callback:

  //add callback for custom version of set thumbnail
  add_action(\'wp_ajax_prism_set_thumbnail\', \'kia_set_thumbnail_callback\');

  // the function name must match the above passed name
  function kia_set_thumbnail_callback(){

    $post_ID = intval( $_POST[\'post_id\'] );
    if ( !current_user_can( \'edit_post\', $post_ID ) )
        die( \'-1\' );
    $thumbnail_id = intval( $_POST[\'thumbnail_id\'] );

    check_ajax_referer( "set_post_thumbnail-$post_ID" );

    if ( $thumbnail_id == \'-1\' ) {
        if ( delete_post_thumbnail( $post_ID ) )
            die( _wp_post_thumbnail_html() );
        else
            die( \'0\' );
    }

    if ( set_post_thumbnail( $post_ID, $thumbnail_id ) )
        $msg = get_the_post_thumbnail( $post_ID, array(35,35));
        die($msg);
    die( \'0\' );
}