表單生成與hasError（）進行驗證拋出錯誤類型錯誤的錯誤：無法讀取未定義

Question

你好我在執行中component.ts使用表單生成

在角2形式我已經實現的特性「hasError」我使用formGroup

形式下面是我的代碼

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: [''], 

    }); 

} 

這是工作的罰款。但未來在前端顯示驗證時

我用這樣的

<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> 

這是工作，但引發錯誤控制檯類似下面

錯誤類型錯誤：無法讀取的未定義的屬性「hasError」

請幫我一下如何排序。

謝謝。

Answer 1

你應該使用這樣的：

<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>