好吧，我在几个小时的不眠之夜后找到了它：

呼叫$this->get_field_id($key) 在Widget构造函数中是一个错误。必须在function form() （可能是由于使用了一些全局变量*）

大多数痛苦来自于这样一个事实，即它没有将小部件保存在侧栏中。原因是，在数据库的开发过程中，一切都变得一团糟。Wordpress似乎期望id_base 以及数据库中实际创建的实例。如果您想要清晰的图片，请尝试更改id_base 新鲜的东西

最后的工作代码：

class DW_Center_Address_Widget extends WP_Widget {

    // I changed the id_base a couple of times
    const ID = \'dwbn-center-address-3\';

    var $formDefinition;
    var $widgetArguments = [];

    function __construct() {
        //Constructor
        $widget_ops = array(\'classname\' => self::ID, \'description\' => Connector::get_translation( \'Displays the address of a Center stored in the SSO.\' ) );
        parent::__construct( self::ID, Connector::get_translation(\'DW Center Address\'), $widget_ops );

        $this->formDefinition = [
            // a title field makes the wordpress widget definetly more usefull, it will display this value in gray
            [
                \'type\' => \'text\',
                \'key\' => Shortcodes::ATTR_TITLE,
                \'label\' => __(\'Title\'), // just take the standard translation
                \'value\' => \'\' // the default value
            ],
            [
                \'type\' => \'info\',
                \'label\' => Connector::get_translation("Change Center data at the:") . \'<br/>\' . \'<a target="_blank" class="button" style="margin-top: 10px;" href="the.sso">\' . Connector::get_translation(\'SSO\') . \'</a>\'
            ],
            [
                \'type\' => \'text\',
                \'key\' => Shortcodes::ATTR_SLUG,
                \'label\' => Connector::get_translation(\'Center Slug or Id\'),
                \'value\' => \'\' // the default value
            ]
        ];

        foreach ($this->formDefinition as $def) {
            if (array_key_exists(\'key\', $def)) {
                $this->widgetArguments[$def[\'key\']] = array_key_exists(\'value\', $def) ? $def[\'value\'] : \'\';
            }
        }
    }

    /**
     * @param array $args - holds context information
     * @param array $instance - the actual parameters
     */
    function widget($args, $instance) {
        echo Shortcodes::dw_center($instance);
    }

    function update($new_instance, $old_instance) {
        $instance = [];

        foreach ($this->widgetArguments as $key => $val) {
            $instance[ $key ] = trim(strip_tags($new_instance[ $key ]));
        }

        return $instance;
    }

    function form( $instance ) {
        $instance = wp_parse_args( (array) $instance, $this->widgetArguments );
        $form = [];

        for ($i = 0; $i < count($this->formDefinition); $i++) {

            $form[] = $this->formDefinition[$i];

            if (array_key_exists(\'key\', $form[$i])) {
                $key = $form[$i][\'key\'];

                if (array_key_exists($key, $instance)) {
                    $form[$i][\'value\'] = $instance[$key];
                }

                // it is important, that this functions are called during runtime, otherwise the widget ids will not be correct
                $form[$i][\'id\'] = $this->get_field_id($key);
                $form[$i][\'name\'] = $this->get_field_name($key);
            }
        }

        echo Template::render(\'admin/forms/widget_form.html.twig\', [
            \'form\' => $form
        ]);

    }
}

* 这是为什么不依赖全局名称空间的又一个例子——wordpress不会改变，但如果你构建了一个数百万人将使用的新系统，请尽量避免；）。