Angular 2路由器没有基本href集

Question

我收到一个错误，找不到原因。这是错误：

EXCEPTION: Error during instantiation of LocationStrategy! (RouterOutlet -> Router -> Location -> LocationStrategy).
    angular2.dev.js:23514 EXCEPTION: Error during instantiation of LocationStrategy! (RouterOutlet -> Router -> Location -> LocationStrategy).BrowserDomAdapter.logError @ angular2.dev.js:23514BrowserDomAdapter.logGroup @ angular2.dev.js:23525ExceptionHandler.call @ angular2.dev.js:1145(anonymous function) @ angular2.dev.js:14801NgZone._notifyOnError @ angular2.dev.js:5796collection_1.StringMapWrapper.merge.onError @ angular2.dev.js:5700run @ angular2-polyfills.js:141(anonymous function) @ angular2.dev.js:5719zoneBoundFn @ angular2-polyfills.js:111lib$es6$promise$$internal$$tryCatch @ angular2-polyfills.js:1511lib$es6$promise$$internal$$invokeCallback @ angular2-polyfills.js:1523lib$es6$promise$$internal$$publish @ angular2-polyfills.js:1494(anonymous function) @ angular2-polyfills.js:243microtask @ angular2.dev.js:5751run @ angular2-polyfills.js:138(anonymous function) @ angular2.dev.js:5719zoneBoundFn @ angular2-polyfills.js:111lib$es6$promise$asap$$flush @ angular2-polyfills.js:1305
    angular2.dev.js:23514 ORIGINAL EXCEPTION: No base href set. Please provide a value for the APP_BASE_HREF token or add a base element to the document.BrowserDomAdapter.logError @ angular2.dev.js:23514ExceptionHandler.call @ angular2.dev.js:1154(anonymous function) @ angular2.dev.js:14801NgZone._notifyOnError @ angular2.dev.js:5796collection_1.StringMapWrapper.merge.onError @ angular2.dev.js:5700run @ angular2-polyfills.js:141(anonymous function) @ angular2.dev.js:5719zoneBoundFn @ angular2-polyfills.js:111lib$es6$promise$$internal$$tryCatch @ angular2-polyfills.js:1511lib$es6$promise$$internal$$invokeCallback @ angular2-polyfills.js:1523lib$es6$promise$$internal$$publish @ angular2-polyfills.js:1494(anonymous function) @ angular2-polyfills.js:243microtask @ angular2.dev.js:5751run @ angular2-polyfills.js:138(anonymous function) @ angular2.dev.js:5719zoneBoundFn @ angular2-polyfills.js:111lib$es6$promise$asap$$flush @ angular2-polyfills.js:1305
    angular2.dev.js:23514 ORIGINAL STACKTRACE:BrowserDomAdapter.logError @ angular2.dev.js:23514ExceptionHandler.call @ angular2.dev.js:1157(anonymous function) @ angular2.dev.js:14801NgZone._notifyOnError @ angular2.dev.js:5796collection_1.StringMapWrapper.merge.onError @ angular2.dev.js:5700run @ angular2-polyfills.js:141(anonymous function) @ angular2.dev.js:5719zoneBoundFn @ angular2-polyfills.js:111lib$es6$promise$$internal$$tryCatch @ angular2-polyfills.js:1511lib$es6$promise$$internal$$invokeCallback @ angular2-polyfills.js:1523lib$es6$promise$$internal$$publish @ angular2-polyfills.js:1494(anonymous function) @ angular2-polyfills.js:243microtask @ angular2.dev.js:5751run @ angular2-polyfills.js:138(anonymous function) @ angular2.dev.js:5719zoneBoundFn @ angular2-polyfills.js:111lib$es6$promise$asap$$flush @ angular2-polyfills.js:1305
    angular2.dev.js:23514 Error: No base href set. Please provide a value for the APP_BASE_HREF token or add a base element to the document.
        at new BaseException (angular2.dev.js:8080)
        at new PathLocationStrategy (router.dev.js:1203)
        at angular2.dev.js:1380
        at Injector._instantiate (angular2.dev.js:11923)
        at Injector._instantiateProvider (angular2.dev.js:11859)
        at Injector._new (angular2.dev.js:11849)
        at InjectorDynamicStrategy.getObjByKeyId (angular2.dev.js:11733)
        at Injector._getByKeyDefault (angular2.dev.js:12048)
        at Injector._getByKey (angular2.dev.js:12002)
        at Injector._getByDependency (angular2.dev.js:11990)

有谁知道为什么路由器会抛出这个？我正在使用 angular2 测试版

这是我的代码：

import {Component} from 'angular2/core';
import { RouteConfig, ROUTER_DIRECTIVES } from 'angular2/router';
import {LoginComponent} from './pages/login/login.component';
import {DashboardComponent} from './pages/dashboard/dashboard.component';
@Component({
    selector: 'app',
    directives:[ROUTER_DIRECTIVES],
    template:`
        <div class="wrapper">
            <router-outlet></router-outlet>
        </div>`
})
@RouteConfig([
    { path: '/',redirectTo: '/dashboard' },
    { path: '/login',name:'login',component: LoginComponent },
    { path: '/dashboard',name:'dashboard',component: DashboardComponent,}
])
export class AppComponent {
}

Answer 1

Angular 7,8 修复在 app.module.ts 中

import {APP_BASE_HREF} from '@angular/common';

在@NgModule 里面添加

providers: [{provide: APP_BASE_HREF, useValue: '/'}]

Answer 2

检查您的 index.html。 如果您不小心删除了以下部分，请将其包含在内就可以了

<base href="/">

<meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="icon" type="image/x-icon" href="favicon.ico">

Answer 3

只是在 index.html 头标签中添加以下代码

   <html>
    <head>
     <base href="/">
      ...

这对我来说就像一个魅力。

Answer 4

使用 Angular 4，您可以通过更新 app.module.ts 文件来解决此问题，如下所示：

在顶部添加import语句如下：

import {APP_BASE_HREF} from '@angular/common';

并在@NgModule内添加以下行

providers: [{provide: APP_BASE_HREF, useValue: '/my/app'}]

参考：https://angular.io/api/common/APP_BASE_HREF

Answer 5

我在 Angular4 和 Jasmine 单元测试中遇到过类似的问题；以下给定的解决方案对我有用

在导入语句下方添加

import { APP_BASE_HREF } from '@angular/common';

为 TestBed 配置添加以下语句：

TestBed.configureTestingModule({
    providers: [
        { provide: APP_BASE_HREF, useValue : '/' }
    ]
})

Answer 6

您还可以通过在 app.module.ts 中包含以下内容来使用基于哈希的导航

import { LocationStrategy, HashLocationStrategy } from '@angular/common';

并将以下内容添加到 @NgModule({ ... })

@NgModule({
  ...
  providers:    [
      ProductService, {
          provide: LocationStrategy, useClass: HashLocationStrategy
      }
  ],
  ...
})

“HashLocationStrategy——在 URL 中添加井号 (#)，井号后的 URL 段唯一标识要用作网页片段的路由。此策略适用于所有浏览器，包括旧浏览器。”

摘自：Yakov Fain Anton Moiseev。 “使用 TypeScript 进行 Angular 2 开发。”

Answer 7

https://angular.io/docs/ts/latest/guide/router.html

在<head> 标记之后添加基本元素。如果app 文件夹是应用程序根目录，就像我们的应用程序一样，请设置href 值准确，如下所示。

<base href="/"> 告诉 Angular 路由器 URL 的静态部分是什么。然后路由器只修改 URL 的剩余部分。

<head>
  <base href="/">
  ...
</head>

或者添加

>= Angular2 RC.6

import {APP_BASE_HREF} from '@angular/common';

@NgModule({
  declarations: [AppComponent],
  imports: [routing /* or RouterModule */], 
  providers: [{provide: APP_BASE_HREF, useValue : '/' }]
]); 

在您的引导程序中。

在旧版本中，导入必须像

import {APP_BASE_HREF} from '@angular/common';
bootstrap(AppComponent, [
  ROUTER_PROVIDERS, 
  {provide: APP_BASE_HREF, useValue : '/' });
]); 

import {provide} from 'angular2/core';
bootstrap(AppComponent, [
  ROUTER_PROVIDERS, 
  provide(APP_BASE_HREF, {useValue : '/' });
]); 

import {APP_BASE_HREF} from 'angular2/router';

>= beta.17

import {APP_BASE_HREF} from 'angular2/platform/common';

另见Location and HashLocationStrategy stopped working in beta.16

Answer 8

从 2.0 测试版开始 :)

import { APP_BASE_HREF } from 'angular2/platform/common';