“AppComponent”类型上不存在属性“alertService”和“options”

Question

我正在我的应用程序中实现警报服务，但是我收到错误Property 'alertService' does not exist on type 'AppComponent'和Property 'options' does not exist on type 'AppComponent'

app.component.html：

<div class="form-group">
   <button [disabled]="frmSignup.invalid" type="submit" class="btn btn-primary btn-block font-weight-bold" 
   (click)="alertService.success('Success!!', options)">Submit</button>
</div>

app.component.ts:

export class AppComponent {
  public frmSignup: FormGroup;
  public message = "Congrats you have successfully created your account";

  constructor(private fb: FormBuilder) {
    this.frmSignup = this.createSignupForm();
  }

  createSignupForm(): FormGroup {
    return this.fb.group(
      {
       ........
      }
    );
  }

  submit() {
    // do signup or something
    console.log(this.frmSignup.value);
    alert(this.message);
  }

Answer 1

您需要在alertService的构造函数中显式注入AppComponent

constructor(private fb: FormBuilder, alertService: AlertService) {
    this.frmSignup = this.createSignupForm();
    this.alertService = alertService;
}

这些选项也需要在组件中设置为公共属性。

---

然而：

更好的选择是创建一个类方法，您可以在单击事件上调用它：

<div class="form-group">
   <button [disabled]="frmSignup.invalid" type="submit" class="btn btn-primary btn-block font-weight-bold" 
   (click)="handleClick()">Submit</button>
</div>

export class AppComponent {
  public frmSignup: FormGroup;
  public message = "Congrats you have successfully created your account";
  options = {};

  constructor(private fb: FormBuilder, private alertService: AlertService) {
    this.frmSignup = this.createSignupForm();
  }

  createSignupForm(): FormGroup {
    return this.fb.group(
      {
       ........
      }
    );
  }

  submit() {
    // do signup or something
    console.log(this.frmSignup.value);
    alert(this.message);
  }
  
  handleClick() {
    this.alertService.success('Success!!', options);
  }
}

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注意：我不明白，为什么提交按钮不调用提交方法......