角材料数据表未加载

Question

我的Angular Material数据表根本没有显示。控制台中没有错误。我可以在页面源代码和tr中看到html标记，但屏幕上没有任何显示。如您所见，我的数据源中有两个项目，并且在html中生成了两个tr。我尝试使用其他数据源没有成功。

这是我的代码：

<div class="mat-elevation-z8">
    <mat-table [dataSource]="myGuests">
        <ng-container matColumnDef="Name">
            <th mat-header-cell *matHeaderCellDef>Name</th>
            <td mat-cell *matCellDef="let guest"> {{ guest.Name }}</td>
        </ng-container>

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

组件代码：

import { Component } from '@angular/core';
import { Guest } from '../models/Guest.model';
import { Title } from '@angular/platform-browser';
import { MatTableDataSource } from '@angular/material';

@Component({
    selector: 'manage-guests',
    templateUrl: './manage-guests.component.html'
})
export class ManageGuestsComponent {
    columnsToDisplay = ['Name'];
    myGuests: Guest[];

    constructor(private service: GuestService, private title: Title) {
        title.setTitle('Ahmad Faiq Ateel - Manage Guests');
        this.myGuests = [
            {Id: 1, Name: 'Taha', Email: '', Public: true, SignDateTime: new Date(2019, 1, 1) },
            {Id: 2, Name: 'Faiq', Email: '', Public: true, SignDateTime: new Date(2019, 1, 1) },
        ];

    }
}

package.json：

{
  "name": "ahmad-faiq-ateel-ui",
  "version": "0.0.0",
  "scripts": {
  "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "^5.2.11",
    "@angular/cdk": "^5.2.5",
    "@angular/common": "~5.0.1",
    "@angular/compiler": "~5.0.1",
    "@angular/core": "~5.0.1",
    "@angular/forms": "~5.0.1",
    "@angular/http": "~5.0.1",
    "@angular/material": "^5.2.5",
    "@angular/platform-browser": "~5.0.1",
    "@angular/platform-browser-dynamic": "~5.0.1",
    "@angular/router": "~5.0.1",
    "angular-in-memory-web-api": "~0.5.1",
    "bootstrap": "^4.3.1",
    "core-js": "^2.5.1",
    "jquery": "^3.4.1",
    "ngx-toastr": "^8.10.2",
    "popper.js": "^1.15.0",
    "rxjs": "5.5.2",
    "systemjs": "0.20.19",
    "zone.js": "^0.8.18"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "~0.12.0",
    "@angular/cli": "^7.2.4",
    "@angular/compiler-cli": "~7.2.0",
    "@angular/language-service": "~7.2.0",
    "@types/jasmine": "~2.8.8",
    "@types/jasminewd2": "~2.0.3",
    "@types/node": "~8.9.4",
    "codelyzer": "~4.5.0",
    "jasmine-core": "~2.99.1",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~3.1.1",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "~2.0.1",
    "karma-jasmine": "~1.1.2",
    "karma-jasmine-html-reporter": "^0.2.2",
    "protractor": "~5.4.0",
    "ts-node": "~7.0.0",
    "tslint": "~5.11.0",
    "typescript": "~3.2.2"
  }
}