我正在尝试角材料表组件。由于某种原因,它不会在组件中渲染任何数据,给我一个错误
Could not find column with id "id"
。我无法理解这一点 - 我的数据中有一行包含 id
列。
我的内存数据服务提供商如下所示:
import { Injectable } from '@angular/core';
import { InMemoryDbService, RequestInfo } from 'angular-in-memory-web-api'
import { Observable } from 'rxjs';
@Injectable({
providedIn: 'root'
})
export class Contact {
id!: string;
name!: string;
email!: string;
}
export class BackendService implements InMemoryDbService {
constructor() { }
createDb(reqInfo?: RequestInfo | undefined): {} | Observable<{}> | Promise<{}> {
let contacts = [
{ id: 1, name: 'Contact 1', email: '[email protected]' },
{ id: 2, name: 'Contact 2', email: '[email protected]' },
{ id: 3, name: 'Contact 3', email: '[email protected]' },
{ id: 4, name: 'Contact 4', email: '[email protected]' }
];
return { contacts };
}
}
我的组件如下所示:
import { Component, OnInit, ViewChild } from '@angular/core';
import { ContactService } from '../contact.service';
import { firstValueFrom } from 'rxjs';
import { Contact } from '../backend.service';
import { MatTableDataSource } from '@angular/material/table';
import { MatPaginator } from '@angular/material/paginator';
import { MatSort } from '@angular/material/sort';
const COLUMNS_SCHEMA = [
{
key: "id",
type: "text",
label: "Id"
},
{
key: "name",
type: "text",
label: "Name"
},
{
key: "email",
type: "text",
label: "E-mail"
},
]
@Component({
selector: 'app-contact-list',
templateUrl: './contact-list.component.html',
styleUrl: './contact-list.component.css'
})
export class ContactListComponent implements OnInit {
@ViewChild('paginator') paginator!: MatPaginator;
@ViewChild(MatSort) sort!: MatSort;
dataSource!: MatTableDataSource<Contact>;
displayedColumns: string[] = COLUMNS_SCHEMA.map((col) => col.key);
columnsSchema: any = COLUMNS_SCHEMA;
contacts: any[] = [];
constructor(private contactService: ContactService) {
}
async ngOnInit(): Promise<void> {
const data: any = await firstValueFrom(this.contactService.getContacts());
console.log(data);
this.contacts = data;
this.dataSource = new MatTableDataSource(this.contacts);
this.dataSource.paginator = this.paginator;
this.dataSource.sort = this.sort;
console.log(this.displayedColumns);
}
}
最后我的模板如下所示:
<mat-table class="lessons-table mat-elevation-z8" [dataSource]="dataSource">
<ng-container matColumnDef="date">
<mat-header-cell *matHeaderCellDef mat-sort-header> Id </mat-header-cell>
<mat-cell *matCellDef="let contact">
<input type="text" matInput [value]="contact.id" readonly>
</mat-cell>
</ng-container>
<mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>
<mat-row *matRowDef="let row; columns: displayedColumns"></mat-row>
</mat-table>
该错误提到您的
<mat-table>
中没有“id”的列定义。您必须定义 displayColumns
数组中提供的所有列。否则,从 displayColumns
数组中删除不需要的元素。
参考 定义列模板。
<mat-table class="lessons-table mat-elevation-z8" [dataSource]="dataSource">
<ng-container matColumnDef="id">
<mat-header-cell *matHeaderCellDef mat-sort-header> Id </mat-header-cell>
<mat-cell *matCellDef="let contact">
<input type="text" matInput [value]="contact.id" readonly />
{{ contact.id }}
</mat-cell>
</ng-container>
<ng-container matColumnDef="name">
<mat-header-cell *matHeaderCellDef mat-sort-header> Name </mat-header-cell>
<mat-cell *matCellDef="let contact">
<input type="text" matInput [value]="contact.name" readonly />
{{ contact.name }}
</mat-cell>
</ng-container>
<ng-container matColumnDef="email">
<mat-header-cell *matHeaderCellDef mat-sort-header> Email </mat-header-cell>
<mat-cell *matCellDef="let contact">
<input type="text" matInput [value]="contact.email" readonly />
{{ contact.email }}
</mat-cell>
</ng-container>
<mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>
<mat-row *matRowDef="let row; columns: displayedColumns"></mat-row>
</mat-table>