使用formcontrol验证md-datepicker

问题描述

我是棱角材料2的新手，并试图验证出生日期(DOB)表单字段，例如官方Angular网站中的以下示例

I'm new to angular material 2, and trying to validate the Date of Birth(DOB) form field like following example in Official Angular Website

因此，在 input-errors-example.html 中，我添加了如下所示的表单字段

So in input-errors-example.html I added form field like following

  <md-form-field class="example-full-width">
    <input mdInput [mdDatepicker]="picker" placeholder="Choose a date" [formControl]="dobFormControl" onkeypress='return (event.charCode >= 48 && event.charCode <= 57) || event.charCode == 47' maxlength="10">
    <md-datepicker-toggle mdSuffix [for]="picker"></md-datepicker-toggle>
    <md-datepicker #picker></md-datepicker>
    <md-error *ngIf="dobFormControl.hasError('required') || dobFormControl.hasError('pattern')">
      Please enter a valid Date
    </md-error>
  </md-form-field>

然后在 input-errors-example.ts 文件中，我添加了自定义正则表达式以接受 MM/DD/YYYY 格式

then in input-errors-example.ts file I added custom regular expression to accept MM/DD/YYYY format

import {Component} from '@angular/core';
import {FormControl, Validators} from '@angular/forms';

const DOB_REGEX = /^(?:(?:31(\/|-|\.)(?:0?[13578]|1[02]))\1|(?:(?:29|30)(\/|-|\.)(?:0?[1,3-9]|1[0-2])\2))(?:(?:1[6-9]|[2-9]\d)?\d{2})$|^(?:29(\/|-|\.)0?2\3(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00))))$|^(?:0?[1-9]|1\d|2[0-8])(\/|-|\.)(?:(?:0?[1-9])|(?:1[0-2]))\4(?:(?:1[6-9]|[2-9]\d)?\d{2})$/;

@Component({
  selector: 'input-errors-example',
  templateUrl: 'input-errors-example.html',
  styleUrls: ['input-errors-example.css'],
})
export class InputErrorsExample {


    dobFormControl = new FormControl('', [
        Validators.required,
        Validators.pattern(DOB_REGEX)
    ]);

} 

对于上面的示例，这是 Plunker ，但是在这里我无法选择日期或看不到任何错误消息.

This is the Plunker for above example, but here I cannot select a date or cannot see any error message.

推荐答案

要使FormControl与正则表达式一起使用，必须使用null而不是''空字符串来实例化FormControl:

For your FormControl to work with your regex, you have to instantiate the FormControl with null instead of '' empty string:

dobFormControl = new FormControl(null, [
        Validators.required,
        Validators.pattern(DOB_REGEX)
    ]);

您现在正在工作的朋克此处

Your working now plunker here

这篇关于使用formcontrol验证md-datepicker的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！