删除后如何重新加载数据？

Question

我在我的应用程序中创建了一些 post 作为 html 卡片。我有一个名为 PostList 的组件，我在其中显示所有这些卡片。在每张卡片上，我都有一个删除按钮来删除该特定卡片，该按钮有效，但在我删除一张卡片后，它不会从我的 post 列表中消失，直到我手动刷新页面。这是我的名片：

<div class="card-body">
      <h5 class="card-title cut_text">{{post.title}}</h5>
      <p class="card-text cut_text" style="text-align: left;">
        {{post.text}}
      </p>
      <a href="#" class="btn btn-primary read" routerLink='/posts/{{post.id}}' style="justify-content: center;"><span>Read more</span></a>
      <button *appHasRole='["Admin"]' class="ml-5" (click)="deletePost(post.id)" type="button" style="box-shadow: 1px 1px grey;"><em class="fa fa-trash"></em></button>
</div>

这是删除函数：

@Component({
  selector: 'app-post-card',
  templateUrl: './post-card.component.html',
  styleUrls: ['./post-card.component.css']
})
export class PostCardComponent implements OnInit {
  @Input() post: Post;
  posts: Post[];
  model: any = {};
  user: User;
  postId: number;

  constructor(private postService: PostsService, private toastr: ToastrService, 
      private route: ActivatedRoute, public accountService: AccountService) {}

 ngOnInit(): void {

    this.route.params.subscribe((params) => {
      console.log(params);
      this.postId = params['id'];
    });
}
deletePost(id: number) {
    this.postService.deletePost(id).subscribe(() =>{
      this.toastr.success('Deleted');
    }, error => {
      console.log(error);
      this.toastr.error(error.error);
    });
  }
}

这是 post 列表的 html：

 <div  class=" container mt-3" >
        <span *ngFor="let post of posts">
            <app-post-card [post]="post" class="item" ></app-post-card>
        </span>
 </div>

这是加载 posts 的方法：

export class PostListComponent implements OnInit {
  posts: Post[];
  post: Post;
  pagination: Pagination;
  postParams: PostParams = new PostParams();

  constructor(private postService: PostsService) { }

  ngOnInit(): void {
    this.loadPosts();
  }

  loadPosts() {
    this.postService.getPosts(this.postParams).subscribe(response => {
      this.posts = response.result;
      this.pagination = response.pagination;
    });
  }

}

我试过删除卡片后调用loadPosts()方法，虽然效率不高，但还是不行，还是要刷新页面。怎样才能让它在我删除后自动消失？

Answer 1

您可以使用子组件中的 @Output 发送已删除的 id 并从父组件中的 posts 变量中删除与此 id 对应的元素组件。

post-card.component.ts

import { Component, Input, Output, EventEmitter } from '@angular/core';

@Component({
  selector: 'app-post-card',
  templateUrl: './post-card.component.html',
  styleUrls: ['./post-card.component.css']
})
export class PostCardComponent implements OnInit {
  @Input() post: Post;
  @Output() postRemoved = new EventEmitter();     // <-- custom event

  posts: Post[];
  model: any = {};
  user: User;
  postId: number;

  constructor(private postService: PostsService, private toastr: ToastrService, 
      private route: ActivatedRoute, public accountService: AccountService) {}

  ngOnInit(): void {
    this.route.params.subscribe((params) => {
      console.log(params);
      this.postId = params['id'];
    });
  }

  deletePost(id: number) {
    this.postService.deletePost(id).subscribe(() =>{
      this.toastr.success('Deleted');
      this.postRemoved.emit(id);           // <-- emit the id in the event
    }, error => {
      console.log(error);
      this.toastr.error(error.error);
    });
  }
}

post-list.component.html

<div  class=" container mt-3" >
  <span *ngFor="let post of posts">
    <app-post-card (postRemoved)="onPostRemoved($event)" [post]="post" class="item" ></app-post-card>
  </span>
</div>

post-list.component.ts

onPostRemoved(id: any) {
  this.posts = JSON.parse(JSON.stringify(     // <-- assign a deep clone   
    this.posts.filter(post => post.id !== id)
  ));
}

删除后如何重新加载数据？

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reload

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