我很难试图在表单中使用* ngIf,而ngFormModel会验证表单.
用例是:根据用户输入,隐藏或停用表单中的某些特定字段.但是,如果显示这些输入,则必须对其进行验证.
当只需要基本验证时,我可以做一个或另一个:
>如果仅需要输入,则使用ngControl并且需要使用A-OK
>如果需要特定的格式,可以使用pattern属性.这不是Angular,但它有效.
但是为了实现更复杂的验证,我一直在尝试使用ngControl耦合到ngFormModel,以便使用自定义检查.我使用了以下页面中的代码:
How to add form validation pattern in angular2(和那里引用的链接)
Angular2 Forms :Validations,ngControl,ngModel etc
我的代码如下:
HTML
<div> <h1>Rundown of the problem</h1> <form (ngSubmit)="submitForm()" #formState="ngForm" [ngFormModel]="myForm"> <div class="checkBox"> <label> <input type="checkBox" [(ngModel)]="model.hideField" ngControl="hideField"> Is the input below useless for you ? </label> </div> <div *ngIf="!model.hideField"> <div class="form-group"> <label for="optionalField">Potentially irrelevant field </label> <input type="text" class="form-control" [(ngModel)]="model.optionalField" ngControl="optionalField" required #optionalField="ngForm"> <div [hidden]="optionalField.valid || optionalField.pristine" class="alert alert-warning"> This input must go through myCustomValidator(),so behave. </div> </div> </div> <button type="submit" class="btn btn-primary" [disabled]="!formState.form.valid">I can't be enabled without accessing the input :(</button> <button type="submit" class="btn btn-default">Submit without using form.valid (boo !)</button> </form> </div>
打字稿
import {Component,ChangeDetectorRef,AfterViewInit } from 'angular2/core'; import {NgForm,FormBuilder,Validators,ControlGroup,FORM_DIRECTIVES} from 'angular2/common'; @Component({ selector: 'accueil',templateUrl: 'app/accueil.component.bak.html',directives:[FORM_DIRECTIVES],providers: [FormBuilder] }) export class AccueilComponent implements AfterViewInit { private myForm: ControlGroup; model: any; constructor(fb: FormBuilder,cdr: ChangeDetectorRef) { this.cdr = cdr ; this.model = {} ; this.myForm = fb.group({ "hideField": [false],"optionalField": [this.model.optionalField,Validators.compose([this.myCustomValidator])] }); } ngAfterViewInit() { // Without this,I get the "Expression has changed after it was checked" exception. // See also : https://stackoverflow.com/questions/34364880/expression-has-changed-after-it-was-checked this.cdr.detectChanges(); } submitForm(){ alert("Submitted !"); } myCustomValidator(optionalField){ // Replace "true" by "_someService.someCheckRequiringLogicOrData()" if(true) { return null; } return { "ohNoes": true }; } }
即使使用* ngIf从模板中删除输入,构造函数仍在引用该控件.这反过来阻止我使用[disabled] =“!formState.form.valid”,因为myForm可以理解为INVALID.
我正在瞄准可能使用角度2吗?我相信这不是一个常见的用例,但是再一次使用我目前的知识,我看不出我能如何工作.
谢谢 !
您可以尝试做的是重置您的控件上的验证器.这意味着,当您想要一组新的验证器由于状态更改而被绑定到控件时,您将重新定义验证器函数.
在你的情况下,当你勾选/取消选中你的复选框你想要发生以下情况:
>将输入设置为可选(不需要),但仍然对您的自定义验证器进行验证.
>当复选框被取消选中时,将控件的验证器还原到原始状态.
>再次验证控件,以便更新form.valid.
See my plnkr sample based on Angular.io’s Forms Guide
if (optional) this.heroFormModel.controls['name'].validator = Validators.minLength(3); else this.heroFormModel.controls['name'].validator = Validators.compose([Validators.minLength(3),Validators.required]); this.heroFormModel.controls['name'].updateValueAndValidity();