Angular5:生成全名时检查为空

// app.component.html
<form>
  <label for="firstName">First Name:</label>
  <input type="text" id="firstName" [(ngModel)]="firstName" required>
  
  <label for="lastName">Last Name:</label>
  <input type="text" id="lastName" [(ngModel)]="lastName" required>
  
  <button (click)="submitForm()">Submit</button>
</form>
<p *ngIf="isError">Please enter both first name and last name.</p>

// app.component.ts
import { Component } from '@angular/core';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  firstName: string;
  lastName: string;
  isError: boolean = false;

  submitForm() {
    if (!this.firstName || !this.lastName) {
      this.isError = true;
    } else {
      // Perform form submission or other actions
      this.isError = false;
    }
  }
}