Mat-form-field 不起作用

Question

我使用 Material Angular 制作了一张表格。添加了排序和分页。但是，当我想添加一个用于过滤的表单时，一切都会失败，最终什么也不起作用。我可能做错了什么？该组件已添加到项目模块中。

在使用组件Mat-form-field之前和使用之后。

这是 html 和 ts 文件的示例：

HTML：

<div class="example-container mat-elevation-z8">

  <div class="example-header">
        <mat-form-field>
          <input matInput (keyup)="applyFilter($event.target.value)" placeholder="Filter">
        </mat-form-field>
      </div>

  <mat-table #table [dataSource]="dataSource" matSort>

    <!-- Position Column -->
    <ng-container matColumnDef="position">
      <mat-header-cell *matHeaderCellDef mat-sort-header> 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 mat-sort-header> 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 mat-sort-header> 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 mat-sort-header> 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-paginator #paginator
                [pageSize]="20"
                [pageSizeOptions]="[5, 10, 20]"
                [showFirstLastButtons]="true">
  </mat-paginator>

</div>

TS：

import { Component, OnInit } from '@angular/core';
import { ViewChild} from '@angular/core';
import { MatTableDataSource, MatSort, MatPaginator } from '@angular/material';

@Component({
  selector: 'app-home',
  templateUrl: './home.component.html',
  styleUrls: ['./home.component.scss']
})
export class HomeComponent implements OnInit {
  displayedColumns = ['position', 'name', 'weight', 'symbol'];
  dataSource = new MatTableDataSource(ELEMENT_DATA);

  @ViewChild(MatSort) sort: MatSort;
  @ViewChild(MatPaginator) paginator: MatPaginator;

  applyFilter(filterValue: string) {
    filterValue = filterValue.trim(); // Remove whitespace
    filterValue = filterValue.toLowerCase(); // MatTableDataSource defaults to lowercase matches
    this.dataSource.filter = filterValue;
  }

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

  constructor()  { }


  ngOnInit() {
  }
}

  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'},
  ];

Answer 1

对我来说效果很好。您是否导入了以下依赖项？

npm install --save @angular/material @angular/cdk
npm install --save @angular/animations

在你的app.module.ts中

import {BrowserAnimationsModule} from 
    '@angular/platform-browser/animations';
import { FormsModule } from '@angular/forms';
import { MatInputModule, MatTableModule, MatPaginatorModule, MatSortModule } 
from '@angular/material';

并记住在您的 styles.css 中添加主题：

 @import "~@angular/material/prebuilt-themes/indigo-pink.css";

官方参考：
https://material.angular.io/guide/getting-started

Answer 2

我也有同样的问题。我错过了

MatInputModule

。

FormsModule

是不必要的。

但奇怪的是，当我注释掉

<mat-form-field>

时，它会起作用，但没有预期的格式。

Answer 3

您遇到的错误消息（“mat-form-field”不是已知元素）表明 Angular 无法识别该元素，该元素是 Angular Material 的一部分。

要解决此问题，请确保已将 MatFormFieldModule 导入模块文件（app.module.ts 或使用 mat-form-field 的相关模块）。

以下是如何在模块中导入和包含 MatFormFieldModule 的示例：

@NgModule({
  declarations: [
    // ... your components
  ],
  imports: [
    // ... other modules
    MatFormFieldModule, // Ensure MatFormFieldModule is imported here
  ],
  // ... other configurations
})
export class YourModule { }

确保：

导入语句 (MatFormFieldModule) 存在于文件中。 您使用的模块在 @NgModule 的导入数组中包含 MatFormFieldModule。 进行此更改后，如果您仍然遇到问题，请尝试停止并重新启动 Angular 开发服务器 (ngserve) 以确保更改生效。