角度反应形式在嵌套的 FormGroup 中添加 FormArray 在另一个 FormGroup 中的另一个 FormArray 中

Question

我创建了嵌套的 FormGroup (questionnaire)，其中包含一个 FormArray (section)，其中包含另一个 FormGroup (creatSection())，其中包含另一个 FormArray (question)，其中我们有另一个 formgroup (creatQuestion())，我们在其中有另一个 formarray(answer) 有一个 formgroup (creatAnswer())

除非我想添加另一个问题或另一个答案，否则一切看起来都很好，addSection 工作正常 所以创建是好的，但添加中的问题。 我在想的是，当您创建一个问题时，它不知道要放在哪里，但我不知道如何解决它

我的问卷调查表是这样的

import { Component, OnInit } from '@angular/core';
import { FormBuilder, FormGroup, FormArray } from '@angular/forms'
@Component({
  selector: 'app-questionnaire',
  templateUrl: './questionnaire.component.html',
  styleUrls: ['./questionnaire.component.css']
})
export class QuestionnaireComponent implements OnInit {
questionnaire:FormGroup;
section:FormArray; 
question:FormArray;
answer:FormArray;
  constructor(private fb:FormBuilder) { }

  ngOnInit() {
    this.questionnaire=this.fb.group({ 
      questionnaireName: [''],      
      section : this.fb.array([this.creatSection()])
    })
  }

creatSection():FormGroup{
return this.fb.group({
 sectionName:[''],
 question:this.fb.array([this.creatQuestion()])
}) 
}

addSection(){
 this.section=this.questionnaire.get('section') as FormArray;
  this.section.push(this.creatSection());
}

creatQuestion():FormGroup{
  return this.fb.group({
    questionName:[''],
    type:[''],
    answer:this.fb.array([this.creatAnswer()])
  })
}

addQuestion(){
  this.question=this.creatSection().get('question') as FormArray;
  this.question.push(this.creatQuestion());
}

creatAnswer():FormGroup{
  return this.fb.group({
    id:[''],
    answerName:['']
  })
}

addAnswer(){
  this.answer=this.creatQuestion().get('answer') as FormArray;
  this.answer.push(this.creatAnswer());
}

onSubmit(){
  console.log(this.questionnaire.value); 
}

}

问卷调查表.html是这样的

<h1>questionnaire bla bla</h1>
<!-- <app-section></app-section> -->
<form [formGroup]="questionnaire" (ngSubmit)="onSubmit()">
    <input type="text" placeholder="questionnaire..." formControlName="questionnaireName">
    <ng-container formArrayName="section">
    <div [formGroupName]="i" *ngFor="let ques of questionnaire.get('section').controls;let i = index;">
        
            <input placeholder="section..." formControlName="sectionName" type="text">
            <button (click)="addSection()">add section</button>
            <ng-container formArrayName="question">
            <div [formGroupName]="j" *ngFor="let sec of creatSection().get('question').controls;let j=index;">
                
                    <input placeholder="question..." formControlName="questionName" type="text">
                    <input placeholder="type..." formControlName="type" type="text">
                    <button (click)="addQuestion()">add question</button>
                    <ng-container formArrayName="answer">
                    <div [formGroupName]="k" *ngFor="let ans of creatQuestion().get('answer').controls;let k=index;">
                        
                            <input placeholder="réponse..." formControlName ="answerName" type="text">
                            <button (click)="addAnswer()">add answer</button>
                        </div>
                    </ng-container>    
                </div>
            </ng-container>
        </div>
    </ng-container>
    <button type="submit">submit</button>
</form>
{{questionnaire.value | json}}

Answer 1

首先不要在 .html 中调用 creatSection()

//WRONG
<div [formGroupName]="j" *ngFor="let sec of creatSection().get('question').controls;let j=index;">
//OK
<div [formGroupName]="j" *ngFor="let sec of ques.get('question').controls;let j=index;">

您需要将数组的“索引”作为参数传递（我称为“经典方式”），但您也可以传递数组本身的组

<button (click)="addAnswer(i,j)">add answer</button>
//or
<button (click)="addAnswer(sec)">add answer</button>

在“经典”中

addAnswer(i:number:j:number)
{
   const arraySection=((this.questionnaire.get('section') as FormArray)
   const groupQuestion=(arraySection.get('question') as FormArray).at(i)
   const arrayAnswer=groupQuestion.get('answer') as FormArray
   arrayAnswer.push(this.creatAnswer())
}

如果你传递数组本身

addAnswer(groupQuestion:FormArray)
{
   const arrayAnswer=groupQuestion.get('answer') as FormArray
   arrayAnswer.push(this.creatAnswer())
}

注意：使用 stackblitz 更容易检查，我的代码可能会出错，请理解

Answer 2

感谢@Eliseo，结果看起来像 问卷调查.html

<h1>questionnaire bla bla</h1>
<form [formGroup]="questionnaire" (ngSubmit)="onSubmit()">
    <input type="text" placeholder="questionnaire..." formControlName="questionnaireName">
    <ng-container formArrayName="section">
    <div [formGroupName]="i" *ngFor="let ques of questionnaire.get('section').controls;let i = index;">

            <input placeholder="section..." formControlName="sectionName" type="text">
            <button (click)="addSection()">add section</button>
            <ng-container formArrayName="question">
            <div [formGroupName]="j" *ngFor="let sec of ques.get('question').controls;let j=index;">

                    <input placeholder="question..." formControlName="questionName" type="text">
                    <input placeholder="type..." formControlName="type" type="text">
                    <button (click)="addQuestion(ques)">add question</button>
                    <ng-container formArrayName="answer">
                    <div [formGroupName]="k" *ngFor="let ans of sec.get('answer').controls;let k=index;">

                            <input placeholder="réponse..." formControlName ="answerName" type="text">
                            <button (click)="addAnswer(sec)">add answer</button>
                        </div>
                    </ng-container>    
                </div>
            </ng-container>
        </div>
    </ng-container>
    <button type="submit">submit</button>
</form>
{{questionnaire.value | json}}

问卷调查表看起来像这样

import { Component,OnInit } from '@angular/core';
import { FormBuilder, FormGroup, FormArray } from '@angular/forms'
@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
export class AppComponent implements OnInit  {
  questionnaire:FormGroup;
  section:FormArray;
  question:FormArray;
  answer:FormArray;
  constructor(private fb:FormBuilder) { }
  ngOnInit() {
 this.questionnaire=this.fb.group({ 
      questionnaireName: [''],      
      section : this.fb.array([this.creatSection()])
    })
  }
  creatSection():FormGroup{
return this.fb.group({
 sectionName:[''],
 question:this.fb.array([this.creatQuestion()])
}) 
}

addSection(){
 this.section=this.questionnaire.get('section') as FormArray;
  this.section.push(this.creatSection());
}

creatQuestion():FormGroup{
  return this.fb.group({
    questionName:[''],
    type:[''],
    answer:this.fb.array([this.creatAnswer()])
  })
}

addQuestion(groupSection:FormArray){
  const arrayQuestion=groupSection.get('question') as FormArray
  arrayQuestion.push(this.creatQuestion())
}

creatAnswer():FormGroup{
  return this.fb.group({
    id:[''],
    answerName:['']
  })
}

addAnswer(groupQuestion:FormArray){
    const arrayAnswer=groupQuestion.get('answer') as FormArray
  arrayAnswer.push(this.creatAnswer())
}

onSubmit(){
  console.log(this.questionnaire.value); 
}
}