如何在不重新加载整个站点的情况下更新子组件

Question

我在更新子组件而不重新加载整个站点时遇到问题。

结构父组件是：

父组件：

<div class="overview">
  <div class="vehicle-img">
    <img src={{vehicleImg}} />
  </div>
  <div class="board">
    <div class="board-column company-overview">
      <div class="board-column-header">{{ "COMPANY_OVERVIEW.TITLE" | translate}}</div>
      <div class="board-column-content">
        <app-company-overview [companyOverviewData]="companyOverviewData"></app-company-overview>
        <div *ngIf="!companyOverviewData" class="loading">
          <app-loading></app-loading>
        </div>
      </div>
    </div>
    <div class="board-column feeds">
      <div class="board-column-header">{{ "FEEDS.TITLE" | translate}}</div>
      <div class="board-column-content">
        <app-feeds [FeedsData]="feedsData"></app-feeds>
        <div *ngIf="!feedsData" class="loading">
            <app-loading></app-loading>
      </div>
    </div>
  </div>
</div>

feed组件：

<div class="feeds">
  <mat-card class="feed-card">
    <mat-card-title>
      <div class="title">
        <h3>{{ 'FEEDS.SUBTITLE' | translate}} {{vin}}</h3>
        <hr>
      </div>
    </mat-card-title>
    <app-feed-list></app-feed-list>
    <div class="comment">
      <textarea class="textarea" matInput placeholder="Enter your comment ..." [(ngModel)]="feedsComment"></textarea>
      <button mat-button [disabled]="!feedsComment" (click)="sendComment()">
        <mat-icon class="send-button" matSuffix>send</mat-icon>
      </button>
    </div>
  </mat-card>
</div>

在此组件中，有一个输入字段和一个按钮。如果单击该按钮，它将调用post api服务。将数据发送到后端。

public sendComment(): void {
    alert(this.feedsComment);
    let newFeeds = this.createFeeds();
    this.feedsService.sendFeedsComment(newFeeds).subscribe(() => {
      this.feedsService.getFeedsOverview(this.vin).subscribe((feedsData: Feeds[]) => {
        this.feedsOverviewData = feedsData;
      });
    });
  }

提要-list.html：

<div class="feed-list">
  <table mat-table [dataSource]="dataSource">
    <ng-container matColumnDef="feeds">
      <td mat-cell *matCellDef="let item">
        <mat-card-header>
          <div mat-card-avatar>
            <mat-icon class="avatar">insert_emoticon</mat-icon>
          </div>
          <mat-card-title class="feeds-header"><b>
              <div *ngIf="item.comment !== ''">
                <span>n-Level {{item.user}}</span>
              </div>
              <div *ngIf="item.comment === ''">
                <span>Event</span>
              </div>
            </b>
          </mat-card-title>
          <mat-card-subtitle class="feeds-date">{{item.date | date: 'dd/MM/yyyy'}}</mat-card-subtitle>
        </mat-card-header>
        <mat-card-content>
          <div *ngIf="item.comment !== ''">
            <div class="feeds-info">{{item.comment}}</div>
          </div>
          <div *ngIf="item.comment === ''">
            <div class="feeds-info">FIN search executed by {{item.user}}.</div>
          </div>
        </mat-card-content>
      </td>
    </ng-container>
    <tr mat-row *matRowDef="let row; columns: displayedColumns;"></tr>
  </table>
  <div class="footer">
    <mat-paginator [length]="" [pageSize]="5" [pageSizeOptions]="[5, 10, 20, 30, 40, 50]" showFirstLastButtons></mat-paginator>
  </div>
</div>

和feed-list.ts

export class FeedListComponent implements OnInit {
  displayedColumns: string[] = ['feeds'];
  @Input() feedsOverviewData: Feeds[];
  @ViewChild(MatPaginator) paginator: MatPaginator;
  dataSource = new MatTableDataSource<Feeds>(DATA);
  constructor() {
  }

我这个feed组件，它还有一个子组件feed-list组件

我的问题是，如果电话发送Feeds Comment返回200，那么这个新评论应该显示在feed列表中而不上传整个站点。

我有一个想法，我可以调用api getAllFeeds来获取所有注释，但是这个api将在父组件中使用。

什么是正确的实施方式

有人能帮助我吗？

最好的祝福，

狮子座

Answer 1

你只需要feed-list.ts上的ngOnChanges，当输入参数值发生变化时触发ngOnchanges，所以在你的情况下你的输入参数是feedsOverviewData。这是一个例子。我希望它可以帮助你

feeds.html

   <div class="feeds">
     <mat-card class="feed-card">
      <mat-card-title>
         <div class="title">
            <h3>{{ 'FEEDS.SUBTITLE' | translate}} {{vin}}</h3>
            <hr>
         </div>
     </mat-card-title>
     <app-feed-list  [feedsOverviewData]="feedsOverviewData"></app-feed-list>
     <div class="comment">
       <textarea class="textarea" matInput placeholder="Enter your comment ..." 
          [(ngModel)]="feedsComment"></textarea>
       <button mat-button [disabled]="!feedsComment" (click)="sendComment()">
       <mat-icon class="send-button" matSuffix>send</mat-icon>
     </button>
     </div>
     </mat-card>
     </div>

feeds.ts

   public sendComment(): void {
      alert(this.feedsComment);
    let newFeeds = this.createFeeds();
    this.feedsService.sendFeedsComment(newFeeds).subscribe(() => {
       this.feedsService.getFeedsOverview(this.vin).subscribe((feedsData: Feeds[]) => 
     {
       this.feedsOverviewData = feedsData;
     });
    });
  }

饲料，list.ts

   import { OnChanges, SimpleChanges } from '@angular/core';

   export class FeedListComponent implements OnInit, OnChanges {
   displayedColumns: string[] = ['feeds'];
   @Input() feedsOverviewData: Feeds[];
   @ViewChild(MatPaginator) paginator: MatPaginator;
   dataSource = new MatTableDataSource<Feeds>(DATA);

   constructor() {
   }

    ngOnChanges(changes: SimpleChanges): void {
    if (changes != null) {
         console.log(changes);
            // here you will get the updated data when ever you click the sendComment button on feeds 
     }
    }