Question

我正在尝试使用Angular 5中的服务。这就是我所拥有的：

import { Injectable } from '@angular/core';


@Injectable()
export class DataService {

  constructor() { }

  getData() {
    // don't use 'any', type your data instead!
    return this.httpClient.get<any>('./assets/data.json');
  }

}

我收到以下错误：

属性HttpClient在DataService类型上不存在。

我错过了什么？

Answer 1

您需要从模块中导入HttpClient，如下所示

import {HttpClient} from '@angular/common/http';

你的代码应该是这样的

import { Injectable } from '@angular/core';
import {HttpClient} from '@angular/common/http';

@Injectable()
export class DataService {

  constructor(private httpClient: HttpClient) { }

  getData() {
    // don't use 'any', type your data instead!
    return this.httpClient.get<any>('./assets/data.json');
  }

}

Answer 2

试试这样：

阅读更多关于httpClient here

的信息

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';

@Injectable()
export class DataService {

  constructor(private httpClient: HttpClient) { }

  getData() {
    // don't use 'any', type your data instead!
    return this.httpClient.get<any>('./assets/data.json');
  }

}

Answer 3

考虑按如下方式更新代码：

import { Injectable } from '@angular/core';
import { Http } from "@angular/http";

@Injectable()
export class DataService {

  constructor(private httpClient: Http) { }

  getData() {
    // don't use 'any', type your data instead!
    return this.httpClient.get<any>('./assets/data.json');
  }

}

让我知道它是否有效。

Answer 4

Http Calls已被修改并移至＆＃39; @ angular / common / http＆＃39;作为HttpClient，因为这个想法得到了许多开发人员的支持，因为它转移到了@ angular / common / http＆＃39;来自Angular 4.3，并从Angular 5中弃用了@ angular / http的进一步Http模块。请查看此处的更改：https://jaxenter.com/road-to-angular-5-133253.html。

现在问题，您应该导入HttpClient模块并创建它的实例。所以你的代码就像： -

从@ angular / core＆＃39;导入{Injectable}; 从＆＃39; @ angular / common / http＆＃39;;

导入{HttpClient}

@Injectable（）导出类DataService {

constructor(private _httpClient: HttpClient) { }

getData() {
    // don't use 'any', type your data instead!
    return this._httpClient.get<any>('./assets/data.json');
}

}

Answer 5

对我来说，问题是我的构造函数中没有将 httpClient 列为 private。

原始构造函数：

constructor(
  httpClient: HttpClient
) { }

更新了解决错误的构造函数：

constructor(
  private httpClient: HttpClient
) { }

Angular Service和HttpClient Type不存在

5 个答案: