我是Angular CLI的新手，我正在尝试根据我制作的较旧版本制作我的第一个Web。到目前为止，我可以在根组件内部嵌套和显示组件，但是从那时起，我不能在HTML中引用任何组件。
这是我的代码：
index.html
<!doctype html>
<html lang="es">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Testing Angular</title>
<base href="/">
<link rel="icon" type="image/x-icon" href="favicon.ico">
</head>
<body>
<app-root></app-root>
</body>
</html>
app.module.ts
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { FirstComponent } from './first/first.component';
@NgModule({
declarations: [AppComponent, FirstComponent],
imports: [BrowserModule, AppRoutingModule],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
app.component.ts
import { Component } from '@angular/core';
@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ["./app.component.css"]
})
export class AppComponent {}
app.component.html
<section id="container">
<app-first></app-first>
</section>
<router-outlet></router-outlet>
first.module.ts
import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { SecondComponent } from './second/second.component';
@NgModule({
declarations: [SecondComponent],
imports: [CommonModule]
})
export class FirstModule { }
first.component.ts
import { Component } from '@angular/core';
@Component({
selector: 'app-first',
templateUrl: './first.component.html',
styleUrls: ["./first.component.css"]
})
export class FirstComponent {}
first.component.html
<div id="first">
<app-second></app-second> <!-- This gives an error: it doesn't know whats Second Component -->
</div>
second.module.ts
import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
@NgModule({
imports: [CommonModule],
declarations: []
})
export class SecondModule { }
second.component.ts
import { Component } from '@angular/core';
@Component({
selector: 'app-second',
templateUrl: './second.component.html',
styleUrls: ["./second.component.css"]
})
export class SecondComponent {}
second.component.html
<div id="second">
<span>I'm second component!</span>
</div>
<app-second></app-second>参考给出错误。在Visual Studio中，代码甚至不在建议列表中。
您必须将模块包括在某个地方，有些对您的SecondComponent不了解，请将FirstModule或SecondModule添加到您的AppModule中。查看Angular文档以获得更多策略https://angular.io/docs
imports: [BrowserModule, AppRoutingModule, FirstModule],
通过添加带有要与其他模块共享的组件的导出来修改您的FirstModule。
exports: [SecondComponent]