如何在角度6中以反应形式为日期表单字段设置null

Question

如何为反应形式提交的日期设置 null。我试过但没有工作。任何知道的人请帮助找到解决方案。

app.component.html：

<input type="text" class="form-control" formControlName="publishdate" ngbDatepicker #datepicker="ngbDatepicker">

app.component.ts：

this.registerForm = this.fb.group({}); 
this.registerForm.addControl('publishdate', new FormControl('', null));

Answer 1

把你的input改成这样

<input type="text" class="form-control" formControlName="publishdate" ngbDatepicker #d="ngbDatepicker">

所以，HTML 应该是，

<form class="form-inline" [formGroup]="registerForm">
 <div class="form-group">
   <div class="input-group">
     <input type="text" class="form-control" formControlName="publishdate" ngbDatepicker #d="ngbDatepicker">
     <div class="input-group-append">
       <button class="btn btn-outline-secondary calendar" (click)="d.toggle()" type="button">
       </button>
     </div>
    </div>
   </div>
 </form>

还有TS，

import {Component, OnInit} from '@angular/core';
import { FormControl, FormGroup, FormBuilder, ValidationErrors } from "@angular/forms";

@Component({
  selector: 'ngbd-datepicker-popup',
  templateUrl: './datepicker-popup.html'
})
export class NgbdDatepickerPopup implements OnInit {

  registerForm: FormGroup;

  constructor(private fb: FormBuilder){}

  ngOnInit(){
    this.registerForm = this.fb.group({});
    this.registerForm.addControl('publishdate', new FormControl('', null));
  }
}

工作示例： https://stackblitz.com/edit/ngb-datepicker-validation-opt-out-vk6maq