处理点击链接和更改屏幕上元素颜色之间的逻辑 . 在此示例中,我想在单击链接时更改h1标记的颜色 . 这是我到目前为止所拥有的 . 蓝色链接不会导航到其他组件
app.module.ts
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { RouterModule, Routes } from '@angular/router';
import { AppComponent } from './app.component';
import { BlueComponent } from './blue/blue.component';
import { AppRoutingModule } from './app-routing.module';
import { routes } from './app-routing.module';
@NgModule({
declarations: [
AppComponent,
BlueComponent
],
imports: [
BrowserModule,
AppRoutingModule,
RouterModule.forRoot(routes)
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
app.component.ts
import { Component } from '@angular/core';
import { Router, ActivatedRoute, RouterOutlet, Routes } from '@angular/router';
import { BrowserModule } from '@angular/platform-browser';
import { NgClass, CommonModule } from '@angular/common';
@Component({
selector: 'app-root',
styleUrls: ['./app.component.css'],
template: `<h1 [ngClass]="{'red': (router.url === '/'),
'blue': (router.url === '/blue')}">Color Changer</h1>
<a routerLink='/'>Red</a>
<a routerLink='/blue'>Blue</a>
<router-outlet></router-outlet>
`
})
export class AppComponent {
constructor(router: Router) {}
}
app.component.css
.red {
color: red;
}
.blue {
color: blue;
}
APP-routing.module.ts
import { NgModule } from '@angular/core';
import { RouterModule, Routes } from '@angular/router';
import { AppComponent } from './app.component';
import { BlueComponent } from './blue/blue.component';
export const routes: Routes = [
{ path: '', component: AppComponent },
{ path: 'blue', component: BlueComponent },
];
@NgModule({
imports: [ RouterModule.forRoot(routes) ],
exports: [ RouterModule ]
})
export class AppRoutingModule {}
我一直收到这样一个错误,这个错误阻止我的更改被应用,并且可能阻止我的链接导航:
ERROR TypeError:无法在checkAndUpdateView(core.es5)的Object.debugUpdateDirectives [as updateDirectives](core.es5.js:13058)的Object.eval [as updateDirectives](AppComponent.html:1)中读取未定义的属性'url' .js:12238)在callViewAction(core.es5.js:12603)的execComponentViewsAction(core.es5.js:12535),在checkAndUpdateView(core.es5.js:12244),在callWithDebugContext(core.es5.js:13458)at ViewRef_.webpackJsonp中的Object.debugCheckAndUpdateView [as checkAndUpdateView](core.es5.js:12998)... / .. / .. / core/@angular/core.es5.js.ViewRef_.detectChanges(core.es5.js) :10169)at core.es5.js:4807
Inspector中的来源强调了此代码
<h1 [ngClass]="{'red': (route.url === '/'),
'blue': (route.url === '/blue')}">Color Changer</h1>
这条线有什么问题?
1 回答
您需要使路由器可用于整个组件 .
为此,您可以将变量设为私有
现在路由器可以在整个组件中使用this.router
旁注:以上解决方案是简写