angular - 使用 hasError() 进行验证的表单生成器抛出错误 TypeError : Cannot read property 'hasError' of undefined

Question

您好，我正在使用 Form Builder 以 angular 2 实现一个表单

在 component.ts 中我使用 formGroup 实现了我的表单

下面是我的代码

public myForm: FormGroup;

constructor(private authenticateservice: AuthenticateService,
              private _fb: FormBuilder
             ) {


}

ngOnInit() {

this.myForm = this._fb.group({
      address: [this.userDetails.address, [<any>Validators.required]],
      address2: ['', [<any>Validators.required]],
      city: ['', [<any>Validators.required]],
      company_address: ['', [<any>Validators.required]],
      company_address2: ['', [<any>Validators.required]],
      company_city: ['', [<any>Validators.required]],
      company_country: ['', [<any>Validators.required]],
      company: ['', [<any>Validators.required , Validators.minLength(3)] ],
      company_tax_number: ['', [<any>Validators.required]],
      company_zip: ['', [<any>Validators.required,  Validators.minLength(5) , Validators.maxLength(7)]],
      country: ['', [<any>Validators.required]],
      email: ['', [<any>Validators.required, Validators.email]],
      first_name: [this.userDetails.first_name, [<any>Validators.required]],
      id: ['', [<any>Validators.required]],
      last_name: ['', [<any>Validators.required]],
      phone: ['', [<any>Validators.required, Validators.minLength(10)]],
      zip: ['', [<any>Validators.required , Validators.minLength(5) , Validators.maxLength(7)]],
      user_type: ['2', [<any>Validators.required]],
      terms: [0, [<any>Validators.required]],
      hash_tag: [''],

    });

}

它工作正常。但是在前端显示验证时

我是这样用的

  <div class="form-group row">
    <div class="col-lg-8">
      <label>Address 2</label>
      <textarea class="form-control" placeholder="Address" rows="2" [readonly]="disabled" id="companyaddress2" formControlName="company_address2"></textarea>
      <span class="help-block form-error text-danger small" *ngIf="myForm.controls['company_address2'].hasError('required')">Company Address 2 is Required.</span>
    </div>
  </div>

它正在工作，但在控制台中抛出错误，如下所示

错误类型错误:无法读取未定义的属性“hasError”

请帮我解决这个问题。

谢谢。

Answer 1

你应该像这样使用它:

<span class="help-block form-error text-danger small" 
  *ngIf="myForm.controls['company_address2'].errors?.required &&
  myForm.controls['company_address2'].touched">Company Address 2 is Required </span>