这是我在metabox中创建上载按钮的方法：

文件：template\\u dir/functions。php添加此行：

wp_enqueue_script(\'custom-js\', get_template_directory_uri().\'/js/custom-js.js\');

// Add the Meta Box  
function add_custom_meta_box() {  
    add_meta_box(  
        \'custom_meta_box\', // $id  
        \'Custom Meta Box\', // $title   
        \'show_custom_meta_box\', // $callback  
        \'post\', // $page  
        \'normal\', // $context  
        \'high\'); // $priority  
}  
add_action(\'add_meta_boxes\', \'add_custom_meta_box\');  

// Field Array  
$prefix = \'custom_\';  
$custom_meta_fields = array(
    array(  
        \'name\'  => \'Image\',  
        \'desc\'  => \'A description for the field.\',  
        \'id\'    => $prefix.\'image\',  
        \'type\'  => \'image\'  
    )  
);


// The Callback  
function show_custom_meta_box() {  
global $custom_meta_fields, $post;  
// Use nonce for verification  
echo \'\';  

    // Begin the field table and loop  
    echo \'\';  
    foreach ($custom_meta_fields as $field) {  
        // get value of this field if it exists for this post  
        $meta = get_post_meta($post->ID, $field[\'id\'], true);  
        // begin a table row with  
        echo \' 
                \'.$field[\'label\'].\' 
                \';  
                switch($field[\'type\']) {  
                    // case items will go here 
                        // image  
                        case \'image\':  
                            $image = get_template_directory_uri().\'/images/image.png\';    
                            echo \'\'.$image.\'\';  
                            if ($meta) { $image = wp_get_attachment_image_src($meta, \'medium\'); $image = $image[0]; }                 
                            echo    \' 
                                        
 
                                             
                                             Remove Image 
                                            \'.$field[\'desc\'].\'\';  
                        break;  
                } //end switch  
        echo \'\';  
    } // end foreach  
    echo \'\'; // end table  
}

// Save the Data  
function save_custom_meta($post_id) {  
    global $custom_meta_fields;  

    // verify nonce  
    if (!wp_verify_nonce($_POST[\'custom_meta_box_nonce\'], basename(__FILE__)))   
        return $post_id;  
    // check autosave  
    if (defined(\'DOING_AUTOSAVE\') && DOING_AUTOSAVE)  
        return $post_id;  
    // check permissions  
    if (\'page\' == $_POST[\'post_type\']) {  
        if (!current_user_can(\'edit_page\', $post_id))  
            return $post_id;  
        } elseif (!current_user_can(\'edit_post\', $post_id)) {  
            return $post_id;  
    }  

    // loop through fields and save the data  
    foreach ($custom_meta_fields as $field) {  
        $old = get_post_meta($post_id, $field[\'id\'], true);  
        $new = $_POST[$field[\'id\']];  
        if ($new && $new != $old) {  
            update_post_meta($post_id, $field[\'id\'], $new);  
        } elseif (\'\' == $new && $old) {  
            delete_post_meta($post_id, $field[\'id\'], $old);  
        }  
    } // end foreach  
}  
add_action(\'save_post\', \'save_custom_meta\');

文件：template\\u dir/js/custom js。js公司

    jQuery(function(jQuery) {  

        jQuery(\'.custom_upload_image_button\').click(function() {  
            formfield = jQuery(this).siblings(\'.custom_upload_image\');  
            preview = jQuery(this).siblings(\'.custom_preview_image\');  
            tb_show(\'\', \'media-upload.php?type=image&TB_iframe=true\');  
            window.send_to_editor = function(html) {  
                imgurl = jQuery(\'img\',html).attr(\'src\');  
                classes = jQuery(\'img\', html).attr(\'class\');  
                id = classes.replace(/(.*?)wp-image-/, \'\');  
                formfield.val(imgurl);  //get image url and copy to field
                preview.attr(\'src\', imgurl);  
                tb_remove();  
            }  
            return false;  
        });  

        jQuery(\'.custom_clear_image_button\').click(function() {  
            var defaultImage = jQuery(this).parent().siblings(\'.custom_default_image\').text();  
            jQuery(this).parent().siblings(\'.custom_upload_image\').val(\'\');  
            jQuery(this).parent().siblings(\'.custom_preview_image\').attr(\'src\', defaultImage);  
            return false;  
        });  

    });  

如果您想添加更多类型的字段，可以通过以下网站了解更多信息：Reusable Custom Meta Boxes Part 1: Intro and Basic Fields

有一个很好的与元数据库交互的框架，该框架相当容易使用（有很好的文档记录），并支持多个元数据库选项，包括图像/文件上传。在Github上：Custom Metaboxes and Fields (CMB). 如果要使用CMB，这将是实现上载字段的一种方法。

您需要注册文件上载metabox并向CMB添加呼叫init.php 在中使用以下代码functions.php 文件：

function be_sample_metaboxes( $meta_boxes ) {
    $prefix = \'_cmb_\'; // Prefix for all fields
    $meta_boxes[\'test_metabox\'] = array(
        \'id\' => \'test_metabox\',
        \'title\' => \'Test Metabox\',
        \'pages\' => array(\'post\'), // post type (e.g post, post etc.)
        \'context\' => \'normal\',
        \'priority\' => \'high\',
        \'show_names\' => true, // Show field names on the left
        \'fields\' => array(
            array(
                \'name\' => __( \'Test Image\', \'cmb\' ),
                \'desc\' => __( \'Upload an image or enter a URL.\', \'cmb\' ),
                \'id\'   => $prefix . \'test_image\',
                \'type\' => \'file\',
            ),
        ),
    );

    return $meta_boxes;
}
add_filter( \'cmb_meta_boxes\', \'be_sample_metaboxes\' );

// Initialize the metabox class
add_action( \'init\', \'be_initialize_cmb_meta_boxes\', 9999 );
function be_initialize_cmb_meta_boxes() {
    if ( !class_exists( \'cmb_Meta_Box\' ) ) {
        require_once( \'./metabox/init.php\' );
    }
}

生产线require_once( \'./metabox/init.php\' ); 在第二个函数中，假设您已将CMB元数据库中的文件放置在主题目录中的一个文件夹中，该文件夹名为metabox. 然后在模板中调用此选项（例如。single.php) 您可以使用以下功能

$file = get_post_meta( $post->ID, \'_cmb_test_image\', true );