特定列上的角度表过滤器

Question

在official website 中，有一个example 介绍了如何实现基本上搜索所有列的过滤。我使用完全相同的代码，但我只想让它过滤列Position 和Weight。有没有办法从过滤中排除其他列或只包括这两个？

编辑：我看到我的问题由于不清楚而被投票结束。这是示例中的代码：

<mat-form-field>
  <mat-label>Filter</mat-label>
  <input matInput (keyup)="applyFilter($event)" placeholder="Ex. ium">
</mat-form-field>

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

  <!-- Position Column -->
  <ng-container matColumnDef="position">
    <th mat-header-cell *matHeaderCellDef> No. </th>
    <td mat-cell *matCellDef="let element"> {{element.position}} </td>
  </ng-container>

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

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

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

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

import {Component} from '@angular/core';
import {MatTableDataSource} from '@angular/material/table';

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'},
];

/**
 * @title Table with filtering
 */
@Component({
  selector: 'table-filtering-example',
  styleUrls: ['table-filtering-example.css'],
  templateUrl: 'table-filtering-example.html',
})
export class TableFilteringExample {
  displayedColumns: string[] = ['position', 'name', 'weight', 'symbol'];
  dataSource = new MatTableDataSource(ELEMENT_DATA);

  applyFilter(event: Event) {
    const filterValue = (event.target as HTMLInputElement).value;
    this.dataSource.filter = filterValue.trim().toLowerCase();
  }
}

/* Structure */
table {
  width: 100%;
}

.mat-form-field {
  font-size: 14px;
  width: 100%;
}

这会搜索所有列，但我希望它只搜索上述列。希望这样清楚

我在 SO 上关注了this answer，但它不起作用。

Answer 1

添加自定义过滤函数以覆盖默认过滤谓词。

    ngAfterViewInit() {
    this.dataSource.filterPredicate = function(data, filter: string): boolean {
      return (
        data.position.toString().includes(filter) ||
        data.weight.toString().includes(filter)
      );
    };
  }

如果用户键入 11，则此处的数字将转换为字符串以匹配 11 和 111