Angular 5服务变量值更新

我有两个不相关的组件,我想使用服务将更新的对象从一个发送到另一个.但是我无法在服务中更新对象.

第一部分：

import { SoruService } from '../soru.service';
import { SoruModel,SecenekModel } from '../soruModel';

@Component({
    selector: 'app-first',templateUrl: './first.component.html',styleUrls: ['./first.component.scss'],providers: [SoruService]
})
export class FirstComponent implements OnInit {
    public soruLst : [SoruModel];

    constructor( private soruServis : SoruService ) { }

    ngOnInit(){
        this.soruServis.getirSoruLst().subscribe( veri => {
            this.soruLst = veri as [SoruModel];
        })
    }

    //// MAKE SOME CHANGES ON "soruLst" locally 

    // Send updated 'soruLst' to service 
    updateSoruLst(){
        this.soruServis.updateSoruLst(this.soruLst);
    }

}

我的服务：

import { Injectable } from '@angular/core';
import { SoruModel,SecenekModel } from './soruModel';
import { Http } from '@angular/http';

const metaJson = 'assets/data/Meta.json';

@Injectable()
export class SoruService {

    public sorular = [] as [SoruModel];

    constructor( private http:Http ) {
        this.sorular = [] as [SoruModel];
    }

    getirSoruLst() {
        return this.http.get(metaJson)
        .map(yanit => yanit.json())
    }

    updateSoruLst( soruLst : [SoruModel] ) {
             this.sorular = soruLst;
     }

    getSorular() : [SoruModel] {
        return this.sorular;
    }

}

第二部分：

mport { SoruService } from '../soru.service';
import { SoruModel,SecenekModel } from '../soruModel';

@Component({
    selector: 'app-second',templateUrl: './second.component.html',styleUrls: ['./second.component.scss'],providers: [SoruService]
})
export class SecondComponent implements OnInit {
    public soruLst : [SoruModel];

    constructor( private soruServis : SoruService ) { }

    ngOnInit(){
        this.soruLst = this.soruServis.getSorular();
        console.log(this.soruLst);
    }
}

这就是我想要做的：

>在FirstComponent中,从服务中获取’soruLst’并在本地更改(成功)
>在FirstComponent中,将更改后的’soruLst’发送到服务(Success – updateSoruLst)
>在服务中,更新’sorular’,在’updateSoruLst’中(失败 – 它没有改变,只是在功能范围内改变但我仍然无法读取更新的值).我有问题：

updateSoruLst( soruLst : [SoruModel] ) {
this.sorular = soruLst; }

“this.sorular”值不会全局变化.

>在SecondComponent中,从服务中读取更新的’sorular'(失败,仍然无法读取更新的值)

我想我必须改变我的服务,但找不到我必须改变的地方..

如何在服务中更新我的对象？