Angular 4 - 找不到名称 'HttpClient'

Question

我正在尝试访问 JSON 提要，但在对 the documentation 进行了更改之后我收到以下错误

"Cannot find name 'HttpClient'"

我已经仔细阅读了教程几次，但我一直在努力寻找为什么会出现此错误。

我执行 Http 请求的组件。

rooms.parent.component.ts

import { Component, OnInit } from '@angular/core';

@Component({
 /.../
})

export class RoomParentComponent implements OnInit {
  results: string[];

  // Inject HttpClient into your component or service.
  constructor(private http: HttpClient) {}

  ngOnInit(): void {
    // Make the HTTP request:
    this.http.get(/.../).subscribe(data => {
      this.results = data;
    });
  }
}

app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import {HttpClientModule} from '@angular/common/http';
import { AppComponent } from './app.component';
import { RoomParentComponent } from './rooms.parent.component';

@NgModule({
  declarations: [
    AppComponent,
    RoomParentComponent
  ],
  imports: [
    BrowserModule,
    HttpClientModule,
  ],
  providers: [],
  bootstrap: [AppComponent]
})

export class AppModule { }

如何解决上述错误并将 HttpClient 注入(inject)构造函数？

编辑:我的 Angular 版本是 4.3.2

Answer 1

HttpClient 在 Angular 4.3.0 版本中引入。此外，您还必须确保在主 AppModule 的 imports 元数据中导入并注入(inject)了 HttpClientModule。

// Import HttpClientModule from @angular/common/http in AppModule
import {HttpClientModule} from '@angular/common/http';


//in place where you wanted to use `HttpClient`
import { HttpClient } from '@angular/common/http';