angular - 在 angular 7 中获取路由参数为空

Question

我无法将路由参数检索为空。我正在使用 angular7。
请找到下面的代码

HeaderComponent ts 文件

    import {Router, ActivatedRoute} from '@angular/router';
    constructor(private httpService: HttpClient, private router: Router, private activatedRoute: ActivatedRoute) {
             this.getNewsSelectedFromRouteParam();
        }
    getNewsSelectedFromRouteParam() {
            alert();
            let id = this.activatedRoute.snapshot.paramMap.get('typeId');
            alert(id);
        }
getNewsByCountry(newsTypeSelected: any) {
        this.router.navigate(['/news',newsTypeSelected]);
        this.getNewsSelectedFromRouteParam();
    }

标题 html

<div class=" dropdown-toggle" data-toggle="dropdown">
                XXX
            </div>
            <div class="dropdown-menu">
                <div *ngFor="let cr of country" class="dropdown-item"
                    (click)="getNewsByCountry(cr.value)" >{{cr.name}}</div>
            </div>

应用程序路由 ts 文件

 const routes: Routes = [
        { path: 'news/:typeId', component: XxxComponent },
    { path: '**', component: XxxComponent }
    ];

Answer 1

有两种访问路由参数的方法。

静态(页面加载一次)

动态(如果在您的应用程序中更改参数而不通过浏览器重新加载页面，则获取更新)

您可以在此处获得更多引用: https://angular.io/api/router/ActivatedRouteSnapshot

请参阅以下代码段以了解实现:

let id = this.activatedRoute.snapshot.params.typeId; // any param name after "params"

或者

this.activatedRoute.params.subscribe((params) => {
    let id = params.get('typeId');
});

Make sure you are using above code when component is initialized i.e. in or after ngOnInit().