Angular单组件多Mat-Table调用renderRows()仅单表更新问题

在单个Angular组件中创建多个列结构一致但数据源独立的Mat-Table，点击按钮时希望给所有表格新增一行并实时渲染。目前使用ViewChild获取表格实例，但调用renderRows()后只有其中一个表格能更新。

问题根源 #

当前用@ViewChild(MatTable)获取两个表格实例时，未指定模板引用变量名，Angular会默认返回第一个匹配的MatTable实例，导致table和second_table实际上指向同一个表格，因此只有第一个表格会触发渲染。同时，添加行时第二个表格的数据源索引依赖第一个表格的长度，可能导致数据错位或越界。

解决方法 #

1. 指定ViewChild的模板引用变量：在@ViewChild中传入模板里定义的表格引用名（如#table和#second_table），确保获取到正确的表格实例。
2. 修正数据源索引：第二个表格添加数据时，使用自身数据源的长度作为索引，保证数据同步且无错位。

修改后的TS代码 #

import { Component, ViewChild } from '@angular/core';
import { MatTable } from '@angular/material';

@Component({
  selector: 'table-filtering-example',
  styleUrls: ['table-filtering-example.css'],
  templateUrl: 'table-filtering-example.html',
})
export class TableFilteringExample {
  // 通过模板引用变量获取对应表格实例
  @ViewChild('table') table: MatTable<any>;
  @ViewChild('second_table') second_table: MatTable<any>;
  
  displayedColumns = ['position', 'name', 'weight', 'symbol'];
  table_data: any[] = [];
  second_table_data: any[] = [];

  addRow() {
    // 给第一个表格添加对应索引的数据
    this.table_data.push(ELEMENT_DATA[this.table_data.length]);
    // 第二个表格使用自身数据源长度作为索引，避免数据错位
    this.second_table_data.push(ELEMENT_DATA[this.second_table_data.length]);
    
    // 分别调用两个表格的renderRows()触发渲染
    this.table.renderRows();
    this.second_table.renderRows();
  }
}

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

const ELEMENT_DATA: Element[] = [
  {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'},
  {position: 11, name: 'Sodium', weight: 22.9897, symbol: 'Na'},
  {position: 12, name: 'Magnesium', weight: 24.305, symbol: 'Mg'},
  {position: 13, name: 'Aluminum', weight: 26.9815, symbol: 'Al'},
  {position: 14, name: 'Silicon', weight: 28.0855, symbol: 'Si'},
  {position: 15, name: 'Phosphorus', weight: 30.9738, symbol: 'P'},
  {position: 16, name: 'Sulfur', weight: 32.065, symbol: 'S'},
  {position: 17, name: 'Chlorine', weight: 35.453, symbol: 'Cl'},
  {position: 18, name: 'Argon', weight: 39.948, symbol: 'Ar'},
  {position: 19, name: 'Potassium', weight: 39.0983, symbol: 'K'},
  {position: 20, name: 'Calcium', weight: 40.078, symbol: 'Ca'},
];

HTML代码（无需修改） #

<div class="example-container mat-elevation-z8">
  <mat-table #table [dataSource]="table_data">
    <!-- Position Column -->
    <ng-container matColumnDef="position">
      <mat-header-cell *matHeaderCellDef> No. </mat-header-cell>
      <mat-cell *matCellDef="let element"> {{element.position}} </mat-cell>
    </ng-container>

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

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

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

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

  <mat-table #second_table [dataSource]="second_table_data">
    <!-- Position Column -->
    <ng-container matColumnDef="position">
      <mat-header-cell *matHeaderCellDef> No. </mat-header-cell>
      <mat-cell *matCellDef="let element"> {{element.position}} </mat-cell>
    </ng-container>

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

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

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

    <mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>
    <mat-row *matRowDef="let row; columns: displayedColumns;"></mat-row>
  </mat-table>
</div>
<button (click)="addRow()">ReRender</button>

内容的提问来源于stack exchange，提问作者noname