angular - 类 'HubConnection' 的构造函数是私有(private)的，只能在类声明中访问

Question

我正在尝试实现一个 Angular 和信号器项目。我从 Medium 获取样本

我已经安装了所有必要的包，并且在 app.component.ts 中有以下代码:

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

import { Message } from 'primeng/api';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'PROJECT TITLE';
  base_url = 'http://localhost:8081/';

  hubConnecton: HubConnection;
  msgs: Message[] = [];

  constructor() { 

  }

  ngOnInit(): void {
    this.hubConnecton = new HubConnection(this.base_url);
  }
}

但我在 = new HubConnection(this.base_url); 中收到一条错误消息:Constructor of class 'HubConnection' is private and only accessible within the class declaration.

我需要你的帮助。谢谢。

Answer 1

您必须使用 HubConnectionBuilder()。

import { Component, OnInit } from '@angular/core';
import { HubConnection, HubConnectionBuilder } from '@aspnet/signalr';
import { Message } from 'primeng/api';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {

  public _hubConnecton: HubConnection;
  msgs: Message[] = [];

  constructor() { }

  ngOnInit(): void {
    this._hubConnecton = new HubConnectionBuilder().withUrl("http:/:localhost:1874/notify").build();
    this._hubConnecton
      .start()
      .then(() => console.log('Connection started!'))
      .catch(err => console.log('Error while establishing connection :('));

    this._hubConnecton.on('BroadcastMessage', (type: string, payload: string) => {
      this.msgs.push({ severity: type, summary: payload });
    });
  }
}