Angular 4 表单验证器 - minLength 和 maxLength 不适用于字段类型编号

Question

我正在尝试开发一个联系表单，我希望用户输入长度在 10-12 之间的电话号码值。

值得注意的是，同样的验证在 Message 字段上进行，它唯一的 number 字段给我带来了麻烦。

I found this answer but it is of no use for me.

我有如下代码:

HTML:

<form [formGroup]="myForm" (ngSubmit)="myFormSubmit()">
      <input type="number" formControlName="phone" placeholder="Phone Number">
      <input type="text" formControlName="message" placeholder="Message">
       <button class="button" type="submit" [disabled]="!myForm.valid">Submit</button>
</form>

TS:

this.myForm = this.formBuilder.group({
     phone: ['',  [Validators.required, Validators.minLength(10), Validators.maxLength(12)]],
     message: ['',  [Validators.required, Validators.minLength(10), Validators.maxLength(100)]]
});`

Answer 1

像下面一样使用它并且完美地工作:

phone: ['',  [Validators.required, Validators.min(10000000000), Validators.max(999999999999)]],

自定义验证服务:

import { AbstractControl, ValidatorFn } from '@angular/forms';

export class customValidationService {
   static checkLimit(min: number, max: number): ValidatorFn {
    return (c: AbstractControl): { [key: string]: boolean } | null => {
        if (c.value && (isNaN(c.value) || c.value < min || c.value > max)) {
            return { 'range': true };
        }
        return null;
    };
  }
}