在动态材质表模板中显示嵌套对象

Question

我想在表格中显示weight.name。我能够通过转换数据来做到这一点。但是，我不想以任何形式操纵数据。我尝试将行模板 (

weight

) 中的

weight.name

更改为

displayedColumns

但根本没有返回任何数据。

App.component.html

<table mat-table [dataSource]="dataSource">
  <ng-container *ngFor="let col of displayedColumns" [matColumnDef]="col">
    <th mat-header-cell *matHeaderCellDef> {{col}} </th>
    <td mat-cell *matCellDef="let element"> {{element[col]}} </td>
  </ng-container>

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

App.component.ts

import { Component } from '@angular/core';

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

const ELEMENT_DATA: PeriodicElement[] = [
  {position: 1, name: 'Hydrogen', weight: {name: 5.55}, symbol: 'H'},
  {position: 2, name: 'Helium', weight: {name: 5.55}, symbol: 'He'},
  {position: 3, name: 'Lithium', weight: {name: 5.55}, symbol: 'Li'},
  {position: 4, name: 'Beryllium', weight: {name: 5.55}, symbol: 'Be'},
  {position: 5, name: 'Boron', weight: {name: 5.55}, symbol: 'B'},
  {position: 6, name: 'Carbon', weight: {name: 5.55}, symbol: 'C'},
  {position: 7, name: 'Nitrogen', weight: {name: 5.55}, symbol: 'N'},
  {position: 8, name: 'Oxygen', weight: {name: 5.55}, symbol: 'O'},
  {position: 9, name: 'Fluorine', weight: {name: 5.55}, symbol: 'F'},
  {position: 10, name: 'Neon', weight: {name: 5.55}, symbol: 'Ne'},
];

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {
  displayedColumns: string[] = ['position', 'name', 'weight', 'symbol'];
  dataSource = ELEMENT_DATA;
}

这是 stackblitz 链接供参考。 https://stackblitz.com/edit/angular-mat-table-dynamic-columns-x36dvr?file=src%2Fapp%2Fapp.component.ts

Answer 1

您的问题是，您将权重列显示为 row[col] 或 rowInstance['weight']，它显示权重对象的

toString()

，导致

[object object]

。

1. 将表格模板修改为：

   <table mat-table [dataSource]="dataSource">
        <ng-container matColumnDef="position"> 
            <mat-header-cell *matHeaderCellDef> Position </mat-header-cell>
            <mat-cell *matCellDef="let row">{{row.position}}</mat-cell>
        </ng-container> 
        <ng-container matColumnDef="name"> 
            <mat-header-cell *matHeaderCellDef> Name </mat-header-cell>
            <mat-cell *matCellDef="let row">{{row.name}}</mat-cell>
        </ng-container>
        <ng-container matColumnDef="weightName"> 
            <mat-header-cell *matHeaderCellDef> Weight </mat-header-cell>
            <mat-cell *matCellDef="let row">{{row.weight.name}}</mat-cell>
        </ng-container>
        <ng-container matColumnDef="symbol"> 
            <mat-header-cell *matHeaderCellDef> Symbol </mat-header-cell>
            <mat-cell *matCellDef="let row">{{row.symbol}}</mat-cell>
        </ng-container>
   
        <mat-header-row *matHeaderRowDef="displayedColumns">
        </mat-header-row>
        <mat-row *matRowDef="let row; columns: displayedColumns;">
        </mat-row>
    </table>
   

并在您的

ts

文件中，将显示列修改为：

  `displayedColumns: string[] = ['position', 'name', 'weightName', 'symbol'];`

https://stackblitz.com/edit/angular-mat-table-dynamic-columns-w7do4c?file=src/app/app.component.html

2. 将上游数据模型转换/扁平化为如下所示，并保持模板不变。

   [{position: 1, name: 'Hydrogen', weightName: 5.55, symbol: 'H'},...]

Answer 2

我也遇到过类似的问题，我解决如下。

1. 更新

   displayedColumns: string[] = ['position', 'name', 'weight.name', 'symbol'];

2. 在

   app.component.ts

   中写一个方法如下

findColumnValue = (element:unknown, column:string):string => <string>column.split('.').reduce((acc, cur) => acc[cur], element);

3. 更新html文件如下

<ng-container [matColumnDef]="column" *ngFor="let column of displayedColumns">
    <th mat-header-cell *matHeaderCellDef mat-sort-header> {{column.split('.')[0]}} </th>
    <td mat-cell *matCellDef="let element"> {{findColumnValue(element, column)}} </td>
</ng-container>

4. 如果你对

   eval

   方法没问题的话，可以按如下方式使用

findColumnValue = (element:unknown, column:string):string => eval(`element.${column}`);

Answer 3

您可以在 displayedColumns 数组中使用点表示法访问嵌套对象

示例：

  displayedColumns: string[] = ['position', 'name', 'weight.name', 'symbol'];

在表格 HTML 中，您需要在

weight.name

 中引用点符号 

matColDef

您的 HTML：

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

Answer 4

我们可以使用点（.）表示法来引用数据集中的嵌套对象值。

const lookUpClients = [
    {shortName: 'KA', entityStatus: { code: 'ACTIV'}}
]

<MaterialTable 
    onRowClick={useCallback((event, data) => setSelectedRow(data))}
    options={{
        exportButton: false,
        filtering: false,
        paging: false,
        search: true,
    }}
    columns={[
        { field: 'shortName', title: 'Short Name' },
        { field: 'entityStatus.code', title: 'Status'}, // we can able to mention in the following way to display data
    ]}
    data={lookUpClients}
    title={''}
/>