Aurelia 中的动态路由 - 更改标题

问：

    { 
        route: 'content/:id',
        name: 'Details', 
        title: 'Details',
        viewPorts: { main: { moduleId: './admin/content/details' }, aside: { moduleId: './admin/content/aside' } }, 
        settings: { menu:menuSection.content, access: { controller: 'content', action: 'get' } }
    },
    { 
        route: 'content/:id',
        name: 'Add', 
        viewPorts: { main: { moduleId: './admin/content/details' }, aside: { moduleId: './admin/content/aside' } }, 
        settings: { menu:menuSection.content, access: { controller: 'content', action: 'get' } }
        title: 'Add',
        href: 'content/0',
        nav: true
    }   


    import {Router} from 'aurelia-router'; 

    activate(){
        if (this.id === 0) {
            this.router.title = "Add";
        } else {
            this.router.title = "Edit";
        }
    }

我正在尝试更改标题，因为它当前对新内容和更新内容都说“添加”。我也尝试过 routeConfig（它抛出了一个错误：未处理的承诺拒绝 TypeError：无法读取未定义的属性“navModel”），只是想知道我是否接近找到正确的代码？我需要做某种推送this.router.push吗？

我相信我可能需要对 UpdateTitle 做一些事情：

class UpdateTitle {
    run(routingContext, next, routeConfig) {
        var instr = routingContext.nextInstructions.find(i => i.params.id !== undefined && i.params.id !== 0 && i.params.id !== '');
        if(instr !== undefined) {
            Unsure what to do here?//routeConfig.navModel.title("TEST");
            debugger;
        }

        return next();
    }
}