配置 angular2 应用程序导航和路由时出错

Error while configuring angular2 app navigation and routing

尝试使用 angular-cli 创建带有 angular2 的应用程序我遇到了以下问题: 我想配置导航和路由,但出现以下错误:

Unhandled Promise rejection: Template parse errors: Can't bind to 'routerLink' since it isn't a known property of 'a'. ("s="navbar navbar-fixed-top navbar-custom">

][routerLink]="['/home']">FiT

应用结构如下:

app/
  core/
    nav/
      nav.component.ts|html|scss  
      core.module.ts
  home/
    home.component.ts|html|scss
  app-routing.module.ts   
  app.component.ts|html|scss   
  app.module.ts

app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { HttpModule } from '@angular/http';

import { AppRoutingModule } from './app-routing.module';
import { CoreModule } from './core/core.module';

import { AppComponent } from './app.component';
import { HomeComponent } from './home/home.component';

@NgModule({
  declarations: [
    AppComponent,
    HomeComponent,
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule,
    AppRoutingModule,
    CoreModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

core.module.ts:

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';

import { NavComponent } from './nav/nav.component';

@NgModule({
  imports: [
    CommonModule // we use ngFor
  ],
  exports: [NavComponent],
  declarations: [NavComponent],
})
export class CoreModule { }

app-routing.module.ts

import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';

import { HomeComponent } from './home/home.component';

const routes: Routes = [
  {
    path: '',
    component: HomeComponent
  },
  {
    path: 'home',
    component: HomeComponent
  },
];

@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule],
  providers: []
})
export class AppRoutingModule { }

nav.component.html

<nav class="navbar navbar-fixed-top navbar-custom">
  <div class="container">
    <a class="navbar-brand"  [routerLink]="['/home']">FiT</a>
    <button class="navbar-toggler hidden-md-up" type="button" data-toggle="collapse" data-target="#fit-nav" aria-controls="fit-nav" aria-expanded="false" aria-label="Toggle navigation">
      &#9776;
    </button>
    <div class="collapse navbar-toggleable-sm" id="fit-nav">
      <ul class="nav navbar-nav pull-md-right">
        <li class="nav-item">
          <a class="nav-link">link</a>
        </li>
        <li class="nav-item">
          <a class="nav-link">link</a>
        </li>
        <li class="nav-item">
          <a class="nav-link">Log in</a>
        </li>
        <li class="nav-item">
          <a class="nav-link">sign up</a>
        </li>
      </ul>
    </div>
  </div>
</nav>

所以我试图找出一个答案,我看到了很多类似的问题,但提出的解决方案没有帮助。

代码中的一切看起来都很好。也许我遗漏了什么?

你有语法错误

<a class="navbar-brand"  routerLink="/home">FiT</a>

指令、组件和管道的范围仅限于声明它们的模块,除非它导入了一个导出这些项目的模块。例如

@NgModule({
  declarations: [ SomeComponentThatUsesRouterLink ]
})
class SomeModule {}

@NgModule({
  imports: [
    SomeModule,  <== SomeComponentThatUsesRouterLink can't use routerLink
    RouterModule
  ],
  declarations: [
    AppComponent <== Can use routerLink
  ]
})
class AppModule {}

在这里,即使 AppModule 导入了 RouterModule,它的范围也仅限于它自己的 declarations,而不是 SharedModule 的,所以 SomeComponentThatUsesRouterLink 不能使用 routerLink 指令。

现在看这里

@NgModule({
  exports: [ RouterModule, CommonModule, FormsModule ]
})
class SharedModule {}

@NgModule({
  imports: [ SharedModule ],
  declarations: [ SomeComponentThatUsesRouterLink ]
})
class SomeModule {}

现在 SomeModule 可以使用 RouteModule 指令,因为它导入了一个导出它的模块

或者如果你想要 SomeModule 可以只导入 RouterModule 本身

@NgModule({
  imports: [ RouterModule ],
  declarations: [ SomeComponentThatUsesRouterLink ]
})
class SomeModule {}

因此,要解决您的特定情况下的问题,您需要将 RouterModule 导入 CoreModule,因为 NavComponent 需要路由器指令