Angular 重复代码的自定义验证器应用模板

Question

我有多个输入字段，其中几乎需要相同的验证。有什么方法可以减少显示错误的重复 HTML 代码。

我的代码如下


              <div colspan="2">
                <input type="text" name="appName" [disabled]="recordCreated" [(ngModel)]="appName" appForbiddenName="Application" minlength="4"
                  required #name="ngModel" [ngClass]="{'has-danger': name.invalid && (name.dirty || name.touched) }" />
                <div *ngIf="name.invalid && (name.dirty || name.touched)" class="alert alert-danger">
                  <div *ngIf="name.errors.required">
                    Name is required.
                  </div>
                  <div *ngIf="name.errors.minlength">
                    Name must be at least 4 characters long.
                  </div>
                  <div *ngIf="name.errors.forbiddenName">
                    Name cannot be Application.
                  </div>
                </div>
              </div>

            <div colspan="2">
                <input type="text" name="appName" [disabled]="recordCreated" [(ngModel)]="desc" appForbiddenName="Application" minlength="4"
                  required #desc="ngModel" [ngClass]="{'has-danger': desc.invalid && (desc.dirty || desc.touched) }" />
                <div *ngIf="desc.invalid && (desc.dirty || desc.touched)" class="alert alert-danger">
                  <div *ngIf="desc.errors.required">
                    Desc is required.
                  </div>
                  <div *ngIf="desc.errors.minlength">
                    Desc must be at least 4 characters long.
                  </div>
                  <div *ngIf="desc.errors.forbiddenName">
                    Desc cannot be Application.
                  </div>
                </div>
              </div>

import { Directive, Input } from '@angular/core';
import { NG_VALIDATORS, Validator, ValidatorFn } from '@angular/forms';
import { AbstractControl } from '@angular/forms/src/model';

export function forbiddenNameValidator(nameRe: RegExp): ValidatorFn {
  return (control: AbstractControl) : {[key: string] : any} | null => {
    const forbidden = nameRe.test(control.value);
    return forbidden ? {'forbiddenName': {value: control.value}} : null;
  };
}

@Directive({
  selector: '[appForbiddenName]',
  providers: [{ provide: NG_VALIDATORS, useExisting: ForbiddenValidatorDirective, multi: true }]
})
export class ForbiddenValidatorDirective implements Validator {

  @Input('appForbiddenName') forbiddenName: string;

  validate(control: AbstractControl): { [key: string]: any } | null {
    return this.forbiddenName ? forbiddenNameValidator(new RegExp
      (this.forbiddenName, 'i'))(control) : null;
  }


}

除了输入字段和强制性 div 标记外，所有其他验证器 html 代码都对每个输入字段重复。在指令中有没有一种方法可以return错误消息模板。而不仅仅是null

Answer 1

您可以创建具有 input 属性的组件，例如

export class YourCustomComponent{
@Input() control:FormControl;
@Input() errMessages:any;//it should be an object like {required:'desc is req'}
constructor(){
}

}

在html

        <div *ngIf="control.invalid && (control.dirty || control.touched)" class="alert alert-danger">
                  <div *ngIf="control.errors.required">
                   errMessages.required
                  </div>
                  ......so on
         </div>

然后在你的输入下使用它，比如

 <your-custom-component [control]="desc" [errMessages]="{required:'desc is required'}"> </your-custom-component>

Angular 重复代码的自定义验证器应用模板

Angular custom validator apply template for repetitive code

angular

html-templates

angular-custom-validators