abp/docs/en/UI/Angular/List-Service.md

Querying Lists Easily with ListService

ListService is a utility service to provide an easy pagination, sorting, and search implementation.

Getting Started

ListService is not provided in root. The reason is, this way, it will clear any subscriptions on component destroy. You may use the optional LIST_QUERY_DEBOUNCE_TIME token to adjust the debounce behavior.

import { ListService } from '@abp/ng.core';
import { BookDto } from '../models';
import { BookService } from '../services';

@Component({
  /* class metadata here */
  providers: [
    // [Required]
    ListService,

    // [Optional]
    // Provide this token if you want a different debounce time.
    // Default is 300. Cannot be 0. Any value below 100 is not recommended.
    { provide: LIST_QUERY_DEBOUNCE_TIME, useValue: 500 },
  ],
  template: `
    
  `,
})
class BookComponent {
  items: BookDto[] = [];
  count = 0;

  constructor(
    public readonly list: ListService,
    private bookService: BookService,
  ) {}

  ngOnInit() {
    // A function that gets query and returns an observable
    const bookStreamCreator = query => this.bookService.getList(query);

    this.list.hookToQuery(bookStreamCreator).subscribe(
      response => {
        this.items = response.items;
        this.count = response.count;
        // If you use OnPush change detection strategy,
        // call detectChanges method of ChangeDetectorRef here.
      }
    ); // Subscription is auto-cleared on destroy.
  }
}

Noticed list is public and readonly? That is because we will use ListService properties directly in the component's template. That may be considered as an anti-pattern, but it is much quicker to implement. You can always use public component properties instead.

Place ListService properties into the template like this:

<abp-table
  [value]="book.items"
  [(page)]="list.page"
  [rows]="list.maxResultCount"
  [totalRecords]="book.totalCount"
  [headerTemplate]="tableHeader"
  [bodyTemplate]="tableBody"
  [abpLoading]="list.isLoading$ | async"
>
</abp-table>

<ng-template #tableHeader>
  <tr>
    <th (click)="nameSort.sort('name')">
      {%{{{ '::Name' | abpLocalization }}}%}
      <abp-sort-order-icon
        #nameSort
        sortKey="name"
        [(selectedSortKey)]="list.sortKey"
        [(order)]="list.sortOrder"
      ></abp-sort-order-icon>
    </th>
  </tr>
</ng-template>

<ng-template #tableBody let-data>
  <tr>
    <td>{%{{{ data.name }}}%}</td>
  </tr>
</ng-template>

Usage with Observables

You may use observables in combination with AsyncPipe of Angular instead. Here are some possibilities:

  book$ = this.list.hookToQuery(query => this.bookService.getListByInput(query));

<!-- simplified representation of the template -->

<abp-table
  [value]="(book$ | async)?.items || []"
  [totalRecords]="(book$ | async)?.totalCount"
>
</abp-table>

<!-- DO NOT WORRY, ONLY ONE REQUEST WILL BE MADE -->

...or...

  @Select(BookState.getBooks)
  books$: Observable<BookDto[]>;

  @Select(BookState.getBookCount)
  bookCount$: Observable<number>;

  ngOnInit() {
    this.list.hookToQuery((query) => this.store.dispatch(new GetBooks(query))).subscribe();
  }

<!-- simplified representation of the template -->

<abp-table
  [value]="books$ | async"
  [totalRecords]="bookCount$ | async"
>
</abp-table>

How to Refresh Table on Create/Update/Delete

ListService exposes a get method to trigger a request with the current query. So, basically, whenever a create, update, or delete action resolves, you can call this.list.get(); and it will call hooked stream creator again.

this.store.dispatch(new DeleteBook(id)).subscribe(this.list.get);

...or...

this.bookService.createByInput(form.value)
  .subscribe(() => {
    this.list.get();

    // Other subscription logic here
  })

How to Implement Server-Side Search in a Table

ListService exposes a filter property that will trigger a request with the current query and the given search string. All you need to do is to bind it to an input element with two-way binding.

<!-- simplified representation -->

<input type="text" name="search" [(ngModel)]="list.filter">