获取路由查询参数

Question

我正在尝试从 rc1 迁移到 rc4，但无法获取查询字符串参数。 ActivatedRoute 对象始终为空。

hero.component.ts

import {Component, OnInit} from "@angular/core";
import {Control} from "@angular/common";
import {ROUTER_DIRECTIVES, ActivatedRoute} from '@angular/router';

@Component({
    template: '../partials/main.html',
    directives: [ROUTER_DIRECTIVES]
})

export class HeroComponent implements OnInit {

    constructor(private _activatedRoute: activatedRoute) {

    }

    ngOnInit() {
        this._activatedRoute.params.subscribe(params => {
            console.log(params);
        });
    }
}

ma​​in.ts

import {bootstrap} from '@angular/platform-browser-dynamic';
import {HTTP_PROVIDERS, RequestOptions, Http} from '@angular/http';
import {AppRouterProviders} from './app.routes';

bootstrap(AppComponent, [
    AppRouterProviders,
    HTTP_PROVIDERS
]);

app.component.ts

import {Component, OnInit} from '@angular/core';
import {HeroComponent} from './hero.component';
import {RouteConfig, Router, ROUTER_DIRECTIVES} from '@angular/router';


@Component({
    selector: 'my-app',
    templateUrl: '../partials/main.html',
    directives: [
        HeroComponent,
        ROUTER_DIRECTIVES
    ]
})

export class AppComponent {
}

partials/main.html

<a class="nav-link" [routerLink]="['/']" [queryParams]="{st: 'new'}">New</a>

app.routes.ts

import {provideRouter, RouterConfig}  from '@angular/router';
import {HeroComponent} from './hero.component';
import {ErrorComponent} from './error.component';

const routes: RouterConfig = [
    {path:'', component: HeroComponent},
    {path:'**', component: ErrorComponent}
];

export const AppRouterProviders = [
    provideRouter(routes)
];

当我点击链接“新建”时，控制台打印出空对象

对象{}

更新

plunker

Answer 1

检查 Angular 文档，它都在那里： https://angular.io/docs/ts/latest/guide/router.html

constructor(
  private route: ActivatedRoute,
  private router: Router,
  private service: HeroService) {}

    ngOnInit() {
      this.sub = this.route.params.subscribe(params => {
         let id = +params['id']; // (+) converts string 'id' to a number
         this.service.getHero(id).then(hero => this.hero = hero);
       });

Answer 2

更新（2.0.0 最终版）

(somepath/:someparam/someotherpath) 你可以使用_router.queryParams.subscribe(...)订阅它们：

export class HeroComponent implements OnInit {
  constructor(private _activatedRoute: ActivatedRoute, private _router:Router) {
    _activatedRoute.queryParams.subscribe(
      params => console.log('queryParams', params['st']));

原创

如果您想要 queryParams 而不是路由参数 (somepath/:someparam/someotherpath)，您可以使用 _router.routerState.queryParams.subscribe(...) 订阅它们：

export class HeroComponent implements OnInit {
  constructor(private _activatedRoute: ActivatedRoute, private _router:Router) {
    _router.routerState.queryParams.subscribe(
      params => console.log('queryParams', params['st']));

Plunker example

Answer 3

我为同样的问题苦苦挣扎了很长时间。 答案很棘手，在文档中指出：

ActivatedRoute：为每个路由提供的服务 包含路由特定信息的组件，例如路由参数、静态数据、解析数据、全局查询参数和全局片段。 here中提到了这一点

诀窍答案是'路由组件'，这意味着ActivatedRoute 将仅适用于路由组件。换句话说，只有路由表中描述的组件。

> 阅读混淆官方文档here。它提到了“与在插座中加载的组件关联的路由”。我们只能猜测什么是插座......

我在独立的 app.module.ts 中编写了一些调查代码来研究这个问题：

import { Component, NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { RouterModule, Routes, ActivatedRoute } from '@angular/router';

@Component({
  selector: 'comp1',
  template: `<h4>comp1 works</h4>`,
})
export class Comp1 { }

@Component({
  selector: 'comp2',
  template: `<h4>comp2 works</h4>`,
})
export class Comp2 { }

@Component({
  selector: 'fail',
  template: `<div>Wrong URL:{{url | json}}</div> <h4>Failure page works</h4>`,
})
export class Fail {
  private url: any;
  constructor(public activeRoute: ActivatedRoute) {
    this.url = activeRoute.snapshot.url
  };

}

@Component({
  selector: 'app-root',
  template: `<div>Base URL:{{url | json}}</div> <router-outlet></router-outlet>`,
})
export class App {
  private url: any;
  constructor(public activeRoute: ActivatedRoute) {
    this.url = activeRoute.snapshot.url
  };
}

const appRoutes: Routes = [
  { path: '1', component: Comp1 },
  { path: '2', component: Comp2 },
  { path: '**', component: Fail }
];

@NgModule({
  imports: [BrowserModule, RouterModule.forRoot(appRoutes)],
  declarations: [App, Comp2, Comp1, Fail],
  bootstrap: [App]
})
export class AppModule { }

---

尝试为以下 URI 运行模块：

• http://localhost:4200/2
• http://localhost:4200/1
• http://localhost:4200/a/b/c

祝你好运，希望代码具有示范性。