Angular2中的反应式FormsModule [英] Reactive FormsModule in Angular2

问题描述

我尝试使用ReactiveFormsModule时在我的项目中添加FormsArray，但是我收到错误，并且显示为:-

I tried to Add FormsArray in my Project while using ReactiveFormsModule but i am receiving the error and it is displayed as :-

找不到具有未指定名称属性的控件. 而且我们也不能通过使用模板驱动的表单来添加FormsArray吗?

Cannot find control with unspecified name attribute. and also can't we add FormsArray by using template driven form ?

下面是我的代码.

recipe-edit.component.ts

recipe-edit.component.ts

<div class="row">
<div class="col-xs-12">
<form [formGroup]="recipeform" (ngSubmit)="onsubmit()" #f="ngForm">
  <div class="row">
    <div class="col-xs-12">
      <button
        type="submit"
        class="btn btn-success" 

        >Save</button>
      <button type="button" class="btn btn-danger" >Cancel</button>
    </div>
  </div>
  <div class="row">
    <div class="col-xs-12">
      <div class="form-group">
        <label for="name">Name</label>
        <input
          type="text"
          id="name"
          formControlName="name"
          class="form-control">
      </div>
    </div>
  </div>
  <div class="row">
    <div class="col-xs-12">
      <div class="form-group">
        <label for="imagePath">Image URL</label>
        <input
          type="text"
          id="imagePath"
          formControlName="image"
          class="form-control"
          >
      </div>
    </div>
  </div>
  <div class="row">
    <div class="col-xs-12" >
      <img  class="img-responsive">
    </div>
  </div>
  <div class="row">
    <div class="col-xs-12">
      <div class="form-group">
        <label for="description">Description</label>
        <textarea
          type="text"
          id="description"
          class="form-control"
          formControlName="description"
          rows="6"></textarea>
      </div>
    </div>
  </div>
  <div class="row">
    <div class="col-xs-12" >
      <div
        class="row"
       formArrayName="ingredients"
       *ngFor="let ctrl of recipeform.get('ingredients').controls;let i=index"
        [formGroupName]="i"          
        style="margin-top: 10px;">
        <div class="col-xs-8">
          <input
            type="text"
            formControlName="name"
            class="form-control"
           >
        </div>
        <div class="col-xs-2">
          <input
            type="number"
            class="form-control"
            formControlName="amount"
           >
        </div>
        <div class="col-xs-2">
          <button
            type="button"
            class="btn btn-danger"
           >X</button>
        </div>
      </div>
      <hr>
      <div class="row">
        <div class="col-xs-12">
          <button
            type="button"
            class="btn btn-success"

            >Add Ingredient</button>
        </div>
      </div>
    </div>
  </div>
</form>

recipe-edit.component.ts

recipe-edit.component.ts

import { Component, OnInit, ViewChild } from '@angular/core';
import {NgForm, FormGroup, FormControl, FormArray} from 
'@angular/forms';
import { Recipeservice } from '../recipe.service';
import { ActivatedRoute, Router } from '@angular/router';
@Component({
 selector: 'app-recipe-edit',
templateUrl: './recipe-edit.component.html',
styleUrls: ['./recipe-edit.component.css']
})
export class RecipeEditComponent implements OnInit {
@ViewChild('f') recipeform:FormGroup
id:number
editmode=false
constructor(private reservice:Recipeservice,private 
route:ActivatedRoute,router:Router) { }

ngOnInit() {
this.route.params.subscribe(
  (params)=>{
    this.id=+params['id']
    console.log(this.id)

    this.initform()
  }
)


}
 onsubmit(){
console.log(this.recipeform)
}
private initform(){
let recipename=''
let recipeimage=''
let recipedescription=''
let recipeingredients=new FormArray([])
this.editmode=true
if(this.editmode){
  const recipe=this.reservice.getrecipe(this.id)
  recipename=recipe.name
  recipeimage=recipe.imagepath
  recipedescription=recipe.description
  if(recipe.ingredients!=null){
    for(let ingredient of recipe.ingredients){
      recipeingredients.push(new FormGroup({
        'name':new FormControl(ingredient.name),
        'amount':new FormControl(ingredient.amount)
      }))
    }
  }
}
this.recipeform=new FormGroup({
  'name':new FormControl(recipename),
  'image':new FormControl(recipeimage),
  'description':new FormControl(recipedescription),
  'ingredients':recipeingredients
})
}

 }

推荐答案

我完全同意 @DeborahK 在以前的 answer 中，您应该在使用反应式表单时遵循这些规则.

I totally agree with the recommendations made by @DeborahK in the previous answer and you should follow those while using Reactive forms.

但是，这些并不是您出错的原因.在HTML模板中，您的FormArray控件层次结构错误.应该是FormArray-> FormGroup-> FormControl，像这样:

However, those are not the reason for your error. In your HTML template, you have a wrong hierarchy of your FormArray control. It should be FormArray --> FormGroup --> FormControl, like this:

<div class="row"
        formArrayName="ingredients"
        *ngFor="let ctrl of recipeform.get('ingredients').controls;let i=index"
        style="margin-top: 10px;">
    <div [formGroupName]="i">
        <div class="col-xs-8">
            <input type="text"
                    formControlName="name"
                    class="form-control">
        </div>
        <div class="col-xs-2">
            <input type="number"
                    class="form-control"
                    formControlName="amount">
        </div>
        <div class="col-xs-2">
            <button type="button"
                    class="btn btn-danger">
                X
            </button>
        </div>
    </div>
</div>

如您所见，我已经将 name 和 amount 控件包装在div中，并将[formGroupName]移到了该包装div中.我没有测试代码，但是它可以解决您的问题.

As you can see, I have wrapped the name and amount control within a div and moved the [formGroupName] to this wrapper div. I didn't test the code but it should solve your problem.

这篇关于Angular2中的反应式FormsModule的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！