Angular 2:无法绑定到“ngModel"，因为它不是“input"的已知属性 [英] Angular 2: Can't bind to 'ngModel' since it isn't a known property of 'input'

问题描述

我正在尝试在 Angular 2 中实现动态表单.我已经向动态表单添加了诸如删除和取消之类的附加功能.我遵循了这个文档:

我对代码进行了一些更改.我在这里遇到错误.

我该如何解决这个错误?

您可以在此处找到完整代码:http://plnkr.co/edit/SL949g1hQQrnRUr1XXqt?p=preview ，它在 plunker 中工作，但不在我的本地系统中.

HTML 代码:

<form [formGroup]="form"><div *ngFor="let question of questions" class="form-row"><label [attr.for]="question.key">{{question.label}}</label><div [ngSwitch]="question.controlType"><input *ngSwitchCase="'textbox'" [formControlName]="question.key"[id]="question.key" [type]="question.type" [(ngModel)]="question.value"><select [id]="question.key" [(ngModel)]="question.value" *ngSwitchCase="'dropdown'" [formControlName]="question.key" ><option *ngFor="let opt of question.options" [ngValue]="opt.key" >{{opt.value}}</option></选择><input *ngSwitchCase="'checkbox'" [(ngModel)]="question.value"[id]="question.key" [type]="question.type" (change)="question.value = ck.checked" #ck [ngModelOptions]="{standalone: true}">
<div class="errorMessage" *ngIf="!form.controls[question.key].valid">{{question.label}} 是必需的</div>

<div class="form-row"><button type="submit" [disabled]="!form.valid" (click)="onSubmit()">保存</button><button type="button" class="btn btn-default" (click)="cancel()">Cancel</button><button type="button" class="btn btn-default" (click)="clear()">清除</button>

</表单><div *ngIf="payLoad" class="form-row"><strong>保存了以下值</strong><br>{{payLoad}}

组件代码:

import { Component, Input, OnInit } from '@angular/core';从@angular/forms"导入 { FormGroup, REACTIVE_FORM_DIRECTIVES };从 './question-base' 导入 { QuestionBase };从 './question-control.service' 导入 { QuestionControlService };从'@angular/common'导入{控制组}；从@angular/core"导入{ChangeDetectorRef}；从'@angular/forms'导入{FormsModule}；@成分({选择器:'动态形式'，templateUrl: 'app/dynamicform/form.component.html',指令:[REACTIVE_FORM_DIRECTIVES]，提供者:[问题控制服务]})导出类 DynamicFormComponent 实现 OnInit {@Input() 问题: QuestionBase[] = [];表格:表格组；有效载荷:任何；payLoad2:任何；questiont: QuestionBase;被质疑: QuestionBase;构造函数(私有 qcs:QuestionControlService，私有 cdr:ChangeDetectorRef){}ngOnInit() {this.form = this.qcs.toFormGroup(this.questions);console.log("表单初始化",this.questions);this.questiont = JSON.parse(JSON.stringify(this.questions));this.questiond = JSON.parse(JSON.stringify(this.questions));}提交(){this.payLoad = JSON.stringify(this.form.value);this.payLoad2=this.payLoad;this.questiont = JSON.parse(JSON.stringify(this.questions));console.log("提交的数据",this.questions);}取消(){console.log("取消");this.questions = JSON.parse(JSON.stringify(this.questiont));}清除(){this.questions = JSON.parse(JSON.stringify(this.questiond));this.questiont = JSON.parse(JSON.stringify(this.questiond));console.log("已清除");this.cdr.detectChanges();}}

解决方案

想出快速解决方案，像这样更新你的@NgModule 代码:

import { NgModule } from '@angular/core';从'@angular/platform-b​​rowser' 导入 { BrowserModule };从'@angular/forms'导入{FormsModule}；从 './app.component' 导入 { AppComponent };@NgModule({进口:[ BrowserModule，FormsModule ]，声明:[ AppComponent ]，引导程序:[ AppComponent ]})导出类 AppModule { }

来源:无法绑定到'ngModel' 因为它不是 'input' 的已知属性

I'm trying to implement Dynamic Forms in Angular 2. I've added additional functionalities like Delete and Cancel to the dynamic forms. I've followed this documentation: https://angular.io/docs/ts/latest/cookbook/dynamic-form.html

I've made some changes to the code. I'm getting error here.

How do i make this error go?

You can find the full code here: http://plnkr.co/edit/SL949g1hQQrnRUr1XXqt?p=preview , which is working in plunker but not in my local system.

Html code:

<div>
  <form [formGroup]="form">

    <div *ngFor="let question of questions" class="form-row">
      <label [attr.for]="question.key">{{question.label}}</label>

  <div [ngSwitch]="question.controlType">

    <input *ngSwitchCase="'textbox'" [formControlName]="question.key"
            [id]="question.key" [type]="question.type" [(ngModel)]="question.value">

    <select [id]="question.key" [(ngModel)]="question.value" *ngSwitchCase="'dropdown'" [formControlName]="question.key" >
      <option *ngFor="let opt of question.options" [ngValue]="opt.key" >{{opt.value}}</option>
    </select>

    <input *ngSwitchCase="'checkbox'"  [(ngModel)]="question.value"
            [id]="question.key" [type]="question.type" (change)="question.value = ck.checked" #ck [ngModelOptions]="{standalone: true}">

  </div> 
  <div class="errorMessage" *ngIf="!form.controls[question.key].valid">{{question.label}} is required</div>
    </div>

    <div class="form-row">
      <button type="submit" [disabled]="!form.valid" (click)="onSubmit()">Save</button>
      <button type="button" class="btn btn-default" (click)="cancel()">Cancel</button>
      <button type="button" class="btn btn-default" (click)="clear()">Clear</button>

    </div>
  </form>

  <div *ngIf="payLoad" class="form-row">
    <strong>Saved the following values</strong><br>{{payLoad}}
  </div>
</div>

Component code:

import { Component, Input, OnInit }  from '@angular/core';
import { FormGroup, REACTIVE_FORM_DIRECTIVES } from '@angular/forms';
import { QuestionBase }                 from './question-base';
import { QuestionControlService }       from './question-control.service';
import { ControlGroup }     from '@angular/common';
import {ChangeDetectorRef} from '@angular/core';
import { FormsModule }   from '@angular/forms';

@Component({
  selector: 'dynamic-form',
  templateUrl: 'app/dynamicform/form.component.html',
  directives: [REACTIVE_FORM_DIRECTIVES],
  providers:  [QuestionControlService]
})
export class DynamicFormComponent implements OnInit {

  @Input() questions: QuestionBase<any>[] = [];
  form: FormGroup;
  payLoad:any;
  payLoad2:any;
  questiont: QuestionBase<any>;
  questiond: QuestionBase<any>;
  constructor(private qcs: QuestionControlService, private cdr: ChangeDetectorRef) {  }
  ngOnInit() {
    this.form = this.qcs.toFormGroup(this.questions);
    console.log("Form Init",this.questions);
    this.questiont = JSON.parse(JSON.stringify(this.questions));
    this.questiond = JSON.parse(JSON.stringify(this.questions));
  }
  onSubmit() {
    this.payLoad = JSON.stringify(this.form.value);
    this.payLoad2=this.payLoad;
    this.questiont = JSON.parse(JSON.stringify(this.questions));
    console.log("Submitted data",this.questions);
  }
  cancel(){
    console.log("Canceled");
    this.questions = JSON.parse(JSON.stringify(this.questiont));
  }
  clear(){
    this.questions = JSON.parse(JSON.stringify(this.questiond));
    this.questiont = JSON.parse(JSON.stringify(this.questiond));
    console.log("Cleared");
    this.cdr.detectChanges();
  }
}

解决方案

Figured out quick solution, update your @NgModule code like this :

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule } from '@angular/forms';
import { AppComponent } from './app.component';

@NgModule({
imports: [ BrowserModule, FormsModule ],
declarations: [ AppComponent ],
bootstrap: [ AppComponent ]
})

export class AppModule { }

Source: Can’t bind to ‘ngModel’ since it isn’t a known property of ‘input’

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