mat-error未显示错误消息angular 5

Question

问题是即使我将文件留空并移动到另一个字段,也不会显示错误消息.我无法在这里找到我做错的事.任何帮助将受到高度赞赏.如果我在onFormValuesChanged()上放置一个断点,它永远不会遇到断点.我试过从构造函数中移动构建部分,但没有任何影响.我不确定在更改字段值时是否触发了表单的值更改事件

角度ver: - 5.2.1

HTML代码

   <div>
    <form [formGroup]="formPersonalRecord">
    <mat-input-container class="full-width-input">
    <input matInput placeholder="First Name" formControlname="firstName">
      <mat-error *ngIf="formErrors.firstName.required">
      Please provide name.
      </mat-error>
     </mat-input-container>
     <mat-input-container class="full-width-input">
     <input matInput placeholder="Last Name" formControlname="lastName">
     </mat-input-container>
      <mat-input-container class="full-width-input">
      <input matInput placeholder="Father's Name" formControlname="fatherName">   
     </mat-input-container>
     <mat-input-container class="full-width-input">
      <input matInput placeholder="Email" formControlname="email">
       <mat-error *ngIf="formErrors.email.required">
        Please provide a email name.
       </mat-error>
     </mat-input-container>
    </form>
    </div>

component.cs

import { Component, OnInit } from '@angular/core';
import { EmployeePersonalRecord } from '../employee/employee-personal-record';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
import { fuseAnimations } from '../../core/animations';
import { HrService } from '../hr.service';



@Component({
  // tslint:disable-next-line:component-selector
  selector: 'app-add-employee',
  templateUrl: './add-employee.component.html',
  styleUrls: ['./add-employee.component.scss'],
  animations: fuseAnimations
})

export class AddEmployeeComponent implements OnInit {

  employeePersonalRecord:   EmployeePersonalRecord     = {} as EmployeePersonalRecord;
  public formPersonalRecord:       FormGroup;
  formErrors: any;
  constructor(private builder: FormBuilder,
    private service: HrService) {
  }

  onFormValuesChanged()
  {
    for ( const field in this.formErrors )
        {
            if ( !this.formErrors.hasOwnProperty(field) )
            {
                continue;
            }
            // Clear previous errors
            this.formErrors[field] = {};
            // Get the control
            const control = this.formPersonalRecord.get(field);
            if ( control && control.dirty && !control.valid )
            {
                this.formErrors[field] = control.errors;
            }
        }
  }

  ngOnInit() {
    this.formPersonalRecord = this.builder.group({
      firstName:              ['', Validators.required],
      lastName:               ['', Validators.required],
      email:                  ['', Validators.required],
      fatherName:             ['', Validators.required],
      dateOfBirth:            ['', Validators.required],
      addressPermanent:       ['', Validators.required],
      addressCurrent:         ['', Validators.required],
      gender:                 ['', Validators.required],
      maritalStatus:          ['', Validators.required],
      religion:               ['', Validators.required],
      cast:                   ['', Validators.required]
    });

    this.formErrors = {
      firstName:        {},
      lastName:         {},
      email:            {},
      fatherName:       {},
      dateOfBirth:      {},
      addressPermanent: {},
      addressCurrent:   {},
      gender:           {},
      maritalStatus:    {},
      religion:         {},
      cast:             {}
    };
    this.formPersonalRecord.valueChanges.subscribe(() => {
      this.onFormValuesChanged();
    });
  }
}

Answer 1

你有一个关于formControlname的拼写错误.它的formControlName大写为N.

分叉的stackblitz

建议:

你不应该在mat-error上添加*ngIf.垫子错误的全部意义在于避免做这样的事情.

你应该使用mat-form-field组件来包装你的输入

所以你可以简单地试试:

<form [formGroup]="formPersonalRecord">
    <mat-form-field class="full-width-input">
       <input matInput placeholder="First Name" formControlName="firstName" />
          <mat-error>
                Please provide name.
          </mat-error>
    </mat-form-field>
...

Answer 2

<mat-error>内容仅在触摸控件或提交表单时显示。*ngIf条件可以指定，这不是问题。<mat-error>例如，当您单击提交按钮以外的另一个按钮时，要显示内容，只需在按钮的处理程序中将所需控件标记为已触摸：

onMyButtonClick() {
  this.form.get('myControl').markAsTouched();
  ...
}

在没有任何与 Angular 有效性管理相关联的约束的情况下在控件下显示消息的另一种方法是使用<mat-hint>代替<mat-error>

Answer 3

这可能已经晚了，但是我遇到了同样的问题，发现我必须先将输入[formControl]绑定到formGroup上，然后才能像这样获得formControl：

<form [formGroup]="formPersonalRecord">

 <mat-input-container class="full-width-input">
   <input matInput placeholder="First Name" [formControl]="formPersonalRecord.get('firstName')">
   <mat-error *ngIf="formPersonalRecord.get('firstName').hasError('required')">
      Please provide name.
   </mat-error>
 </mat-input-container>

Answer 4

此外，mat-error在触摸控件（模糊）或提交表单之前不会显示。