如何获取:来自Angular2中父组件的子路由的id参数

我试图得到:id param定义

RouterModule.forRoot([
  {
    path: 'orders',
    component: ListComponent,
    children: [
      {
        path: 'view/:id',
        component: ViewComponent
      },
    ]
  }
])

route: ActivatedRoute

route.params.subscribe(params => {
  let id = +params['id'];
})

route.firstChild.snapshot.params['id']

route: ActivatedRoute

route.firstChild.params.subscribe(params => {
  let id = +params['id'];
});