至少一个字段需要成角4形式 [英] at least one field is required in angular 4 forms

问题描述

我正在使用角度4形式，并且我有一些字段.和first_name，last_name和company对我来说真的很重要.我想强迫用户填写这三个字段之一.我该怎么做?

I'm using angular 4 forms and I have some fields. and first_name, last_name and company are really important for me. I want to force the user to fill one of these 3 fields. how can I do it?

以下是.ts代码:

this.contactForm = this.fb.group({
        first_name: [null, Validators.compose([Validators.required])],
        last_name: [null, Validators.compose([Validators.required])],
        email: [null, Validators.compose([this.validateEmail])],
        company: [null],
        position: [null],
      });

一个html:

 <form [formGroup]="contactForm" fxLayout="column">
            <md-input-container class="data_light">
              <input class="data_font capital" mdInput placeholder="{{'Contacts.FirstName' | translate}}" [formControl]="contactForm.controls['first_name']">
            </md-input-container>
            <small *ngIf="contactForm.controls['first_name'].hasError('required') && contactForm.controls['first_name'].touched" class="mat-text-warn data_light">{{'Contacts.firstNameReq' | translate}}
            </small>
            <md-input-container class="data_light">
              <input class="data_font capital" mdInput placeholder="{{'Contacts.lastName' | translate}}" [formControl]="contactForm.controls['last_name']">
            </md-input-container>
            <small *ngIf="contactForm.controls['last_name'].hasError('required') && contactForm.controls['last_name'].touched" class="mat-text-warn data_light">{{'Contacts.lastNameReq' | translate}}
            </small>
            <md-input-container class="data_light">
              <input class="data_font" mdInput placeholder="{{'Contacts.email' | translate}}" [formControl]="contactForm.controls['email']"
                (blur)="checkContactEmail()">
            </md-input-container>
            <small *ngIf="contactForm.controls['email'].hasError('validateEmail') && contactForm.controls['email'].dirty" class="mat-text-warn data_light">{{'Contacts.emailValid' | translate}}
            </small>
            <small *ngIf="!emailValid" class="mat-text-warn data_light">{{emailMessage}}
            </small>
            <md-input-container class="data_light">
              <input class="data_font capital" mdInput placeholder="{{'Contacts.Company' | translate}}" [formControl]="contactForm.controls['company']">
            </md-input-container>
            <md-input-container class="data_light">
              <input class="data_font capital" mdInput placeholder="{{'Contacts.Position' | translate}}" [formControl]="contactForm.controls['position']">
            </md-input-container>
          </form>

推荐答案

禁用按钮，直到用户未填写必填字段

Disable your button until required fields are not fileld by user

<button type='submit' [disabled]='!contactForm.valid'> Submit</button>

然后调用此功能以检查禁用

Then call function to check disable like this

<button type='submit' [disabled]='checkValid()'> Submit</button>
checkValid() {
  if(this.contactForm.get('first_name').valid || this.contactForm.get('last_name').valid || this.contactForm.get('email').valid) {
    return false;
  } else {
    return true;
  }
}

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