如何按给定字母过滤表格？答案

【问题标题】：How to filter a table by a given letter?如何按给定字母过滤表格？
【发布时间】：2023-03-17 01:24:01
【问题描述】：

我正在尝试构建一个按字母过滤的表格。因此，如果我单击“A”，则表中应仅显示以“A”开头的数据。我该如何实现？

我已经设置了一个包含硬编码数据的表格。它应该是这样的：

因此，如果我单击“D”，则仅在这种情况下才应显示“Dondini”行。

按照我的表的一些代码sn-ps：

HTML：

    <div class="mat-elevation-z8">
      <table mat-table [dataSource]="dataSource" matSort class="mat-elevation-z8">

...

        <!-- Name Column -->
        <ng-container matColumnDef="name">
          <th mat-header-cell *matHeaderCellDef mat-sort-header> Name </th>
          <td mat-cell *matCellDef="let element"> {{element.name}} </td>
        </ng-container>

...

        <tr mat-header-row *matHeaderRowDef="displayedColumns"></tr>
        <tr mat-row *matRowDef="let row; columns: displayedColumns;"></tr>
      </table>

      <mat-paginator [pageSizeOptions]="[5, 10, 20]" showFirstLastButtons></mat-paginator>
    </div>

TS：

export interface PeriodicElement {
  name: string;
  position: number;
  weight: number;
  symbol: string;
}

const ELEMENT_DATA: PeriodicElement[] = [
  {position: 1, name: 'Hydrogen', weight: 1.0079, symbol: 'H'},
  {position: 2, name: 'Helium', weight: 4.0026, symbol: 'He'},
  {position: 3, name: 'Lithium', weight: 6.941, symbol: 'Li'},
  {position: 4, name: 'Beryllium', weight: 9.0122, symbol: 'Be'},
  {position: 5, name: 'Boron', weight: 10.811, symbol: 'B'},
  {position: 6, name: 'Carbon', weight: 12.0107, symbol: 'C'},
  {position: 7, name: 'Nitrogen', weight: 14.0067, symbol: 'N'},
  {position: 8, name: 'Oxygen', weight: 15.9994, symbol: 'O'},
  {position: 9, name: 'Fluorine', weight: 18.9984, symbol: 'F'},
  {position: 10, name: 'Neon', weight: 20.1797, symbol: 'Ne'},
];

...

export class OpereBuffeComponent implements OnInit {
  displayedColumns: string[] = ['select', 'position', 'name', 'weight', 'symbol'];
  dataSource = new MatTableDataSource<PeriodicElement>(ELEMENT_DATA);
  selection = new SelectionModel<PeriodicElement>(true, []);

  @ViewChild(MatSort, {static: true}) sort: MatSort;
  @ViewChild(MatPaginator, {static: true}) paginator: MatPaginator;

  ngOnInit() {
    this.dataSource.sort = this.sort;
    this.dataSource.paginator = this.paginator;
  }
}

【问题讨论】：

你可以像这样使用管道或过滤数组 array.filter(element => element.name.charAt(0) === filterCharacter);从字符上的clickevent接收过滤字符
查看此答案stackoverflow.com/questions/51515695/… 和现场演示

标签： angular filter angular-material

【解决方案1】：

这样做：

export interface PeriodicElement {
  name: string;
  position: number;
  weight: number;
  symbol: string;
}

const ELEMENT_DATA: PeriodicElement[] = [
  {position: 1, name: 'Hydrogen', weight: 1.0079, symbol: 'H'},
  {position: 2, name: 'Helium', weight: 4.0026, symbol: 'He'},
  {position: 3, name: 'Lithium', weight: 6.941, symbol: 'Li'},
  {position: 4, name: 'Beryllium', weight: 9.0122, symbol: 'Be'},
  {position: 5, name: 'Boron', weight: 10.811, symbol: 'B'},
  {position: 6, name: 'Carbon', weight: 12.0107, symbol: 'C'},
  {position: 7, name: 'Nitrogen', weight: 14.0067, symbol: 'N'},
  {position: 8, name: 'Oxygen', weight: 15.9994, symbol: 'O'},
  {position: 9, name: 'Fluorine', weight: 18.9984, symbol: 'F'},
  {position: 10, name: 'Neon', weight: 20.1797, symbol: 'Ne'},
];

...

export class OpereBuffeComponent implements OnInit {
  displayedColumns: string[] = ['select', 'position', 'name', 'weight', 'symbol'];
  dataSource = new MatTableDataSource<PeriodicElement>(ELEMENT_DATA);
  selection = new SelectionModel<PeriodicElement>(true, []);

  @ViewChild(MatSort, {static: true}) sort: MatSort;
  @ViewChild(MatPaginator, {static: true}) paginator: MatPaginator;

  ngOnInit() {
    this.dataSource.sort = this.sort;
    this.dataSource.paginator = this.paginator;
  }

  receiveFilterChar(c: string) {
   this.dataSource.data = this.ELEMENT_DATA.filter(element => element.name.trim().toLowerCase().charAt(0) === c);
  }
}

您可以只过滤初始数组并将过滤后的结果设置为数据源。如果视图没有更新，您可以使用 ChangeDetectorRef 并检测 UI 更改。

问候

【讨论】：

【解决方案2】：

您可以通过覆盖 MatTableDataSource 的 filterPredicate 来做到这一点，如下所示。

letters: string[] = ['H', 'L', 'B', 'C', 'N'];

ngOnInit() {
    ...
    this.dataSource.filterPredicate = (data: Element, filter: string) => data['name'][0].toLocaleLowerCase() === filter[0];
}

applyFilter(filterValue: string): void {

this.dataSource.filter = filterValue.trim().toLocaleLowerCase();
}

HTML

   <div>
    <input *ngFor="let b of letters" type="button" [value]="b" (click)="applyFilter(b)">
  </div>

找工作StackBlitz

【讨论】：