angular 2构造函数内部服务工作另一个函数内部服务不工作

我的代码

component.ts页面：

import {Component, OnInit, NgModule, VERSION} from '@angular/core';
import {BrowserModule} from '@angular/platform-browser';
import { UserService } from "../services/user.service";
import {Router, ActivatedRoute, Params  } from '@angular/router';

@Component({
       selector: 'app-all-users',
       templateUrl: './all-users.component.html',
       styleUrls: ['./all-users.component.css'],
       providers: [ UserService ]
 })

export class AllUsersComponent{
   users; usersnew; limit; limitnew;  

constructor(public userService: UserService, public router: Router,  public route: ActivatedRoute) {
  this.limit = "0";
  this.limitnew = "0";
  this.userService.getTestUsers(this.limit).subscribe(  users => this.users = users);
}
LoadMore(){  
  this.limit = "12";
  this.limitnew = +this.limitnew + +this.limit;
  this.userService.getTestUsers(this.limitnew).subscribe(  usersnew => this.usersnew = usersnew);
  this.users = [...this.users , ...this.usersnew];
  console.log(this.users);
  }
}

html页面：

<div class="row">
  <div class="col-sm-3 *ngFor="let user of users ;let i = index ">
   <img *ngIf="user.image == ''"  src="http://localhost/assets/images/user.png"  class="user_img">
  </div>
</div>
<button (click)="LoadMore()"> Load More </button>

首先，订阅只能进行一次。如果订阅一次，该函数将在每次都被激发，直到组件被销毁。因此，请从LoadMore函数中删除订阅

首先，您必须从以下角度/核心导入OnInit、OnDestroy lifcycle挂钩

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

在该内部组件之后，进行订阅

ngOnInit() {
    this.subscription = this.userService.getTestUsers(this.limit).subscribe(  users => this.users = users);
  }

当组件被破坏时，不要忘记取消订阅

ngOnDestroy(){
    this.subscription.unsubscribe();
  }

希望这会有所帮助。
尝试以下方法：

export class AllUsersComponent {
    users: Array<any> = [];
    usersnew: Array<any> = [];
    limit; limitnew;

    constructor(public userService: UserService, public router: Router, public route: ActivatedRoute) {
        this.limit = "0";
        this.limitnew = "0";
        this.userService.getTestUsers(this.limit).subscribe(users => this.users = users);
    }

    LoadMore() {
        this.limit = "12";
        this.limitnew = +this.limitnew + +this.limit;
        this.userService.getTestUsers(this.limitnew)
            .subscribe((usersnew) => {
                this.usersnew = usersnew
            }, (error) => {
                console.log('error', error);
            }, () => {
                this.done()
            });
    }

    done() {
        this.users = [...this.users, ...this.usersnew];
        console.log(this.users);
    }
}

导出类AllUsersComponent{
用户：数组=[]；
usersnew:Array=[]；
限制；限制新的；
构造函数（公共用户服务：用户服务，公共路由器：路由器，公共路由：ActivatedRoute）{
此值为0；
此参数为new=“0”；
this.userService.getTestUsers（this.limit）.subscribe（users=>this.users=users）；
}
LoadMore（）{
此值为0.limit=“12”；
this.limitnew=+this.limitnew++this.limit；
this.userService.getTestUsers（this.new）
.订阅（（usersnew）=>{
this.usersnew=usersnew
}，（错误）=>{
console.log（'error'，error）；
}, () => {
这个
});
}
完成（）{
this.users=[…this.users，…this.usersnew]；
console.log（this.users）；
}
}
请给出一个答案-“不工作”的确切含义是什么？在subscribe in loadMore方法中打印日志this.usersnew。如果您在subscribe方法中获得值，那么您的代码是正确的。错误是什么？subscribe inside的console.log，我获得值subscribe的替代值是什么订阅的替代值no alternates for subscribes。。！
export class AllUsersComponent {
    users: Array<any> = [];
    usersnew: Array<any> = [];
    limit; limitnew;

    constructor(public userService: UserService, public router: Router, public route: ActivatedRoute) {
        this.limit = "0";
        this.limitnew = "0";
        this.userService.getTestUsers(this.limit).subscribe(users => this.users = users);
    }

    LoadMore() {
        this.limit = "12";
        this.limitnew = +this.limitnew + +this.limit;
        this.userService.getTestUsers(this.limitnew)
            .subscribe((usersnew) => {
                this.usersnew = usersnew
            }, (error) => {
                console.log('error', error);
            }, () => {
                this.done()
            });
    }

    done() {
        this.users = [...this.users, ...this.usersnew];
        console.log(this.users);
    }
}