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Angular 2:'t bind to ' ngModel ' since it isn' t 'input'的已知属性

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我'm trying to implement Dynamic Forms in Angular 2. I'已向动态表单添加了删除和取消等附加功能 . 我已经按照这个文档:https://angular.io/docs/ts/latest/cookbook/dynamic-form.html

enter image description here

我对代码做了一些更改 . 我在这里收到错误 .

我怎么做这个错误去?

你可以在这里找到完整的代码: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:

<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>

组件代码:

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();
  }
}

12 回答

  • 0

    如果您使用Karma,这个答案可能对您有所帮助:

    我完全按照@ wmnitin的答案提到的那样做,但错误始终存在 . 当使用“ng serve”而不是“karma start”时,它可以工作!

  • 12

    为了在使用AppModule(NgModule)时使ngModel工作,您必须在AppModule中导入FormsModule .

    像这样:

    import { NgModule } from '@angular/core';
    import { BrowserModule  } from '@angular/platform-browser';
    import { FormsModule } from '@angular/forms';
    
    import { AppComponent }   from './app.component';
    
    
    @NgModule({
        declarations: [AppComponent],
        imports: [BrowserModule, FormsModule],
        bootstrap: [AppComponent]
    })
    export class AppModule {}
    
  • 7

    升级到RC5后我遇到类似的错误;即Angular 2:无法绑定到'ngModel',因为它不是'input'的已知属性 .

    Plunker上的代码显示您使用Angular2 RC4,但https://angular.io/docs/ts/latest/cookbook/dynamic-form.html的示例代码使用的是NGModule,它是RC5的一部分 . NGModules是从RC4到RC5的重大变化 .

    此页面介绍了从RC4到RC5的迁移:https://angular.io/docs/ts/latest/cookbook/rc4-to-rc5.html

    我希望这可以解决您所遇到的错误,并帮助您朝着正确的方向前进 .

    简而言之,我必须在app.module.ts中创建一个NGModule:

    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 { }
    

    然后我改变main.ts来使用模块:

    import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
    import { AppModule } from './app.module';
    
    platformBrowserDynamic().bootstrapModule(AppModule);
    

    当然,我还需要更新package.json中的依赖项 . 这是我从package.json的依赖项 . 不可否认,我已经从其他来源(也许是ng docs示例)中将它们混在一起,因此您的里程可能会有所不同:

    ...
    "dependencies": {
        "@angular/common": "2.0.0-rc.5",
        "@angular/compiler": "2.0.0-rc.5",
        "@angular/core": "2.0.0-rc.5",
        "@angular/forms": "0.3.0",
        "@angular/http": "2.0.0-rc.5",
        "@angular/platform-browser": "2.0.0-rc.5",
        "@angular/platform-browser-dynamic": "2.0.0-rc.5",
        "@angular/router": "3.0.0-rc.1",
        "@angular/router-deprecated": "2.0.0-rc.2",
        "@angular/upgrade": "2.0.0-rc.5",
        "systemjs": "0.19.27",
        "core-js": "^2.4.0",
        "reflect-metadata": "^0.1.3",
        "rxjs": "5.0.0-beta.6",
        "zone.js": "^0.6.12",
        "angular2-in-memory-web-api": "0.0.15",
        "bootstrap": "^3.3.6"
      },
    ...
    

    我希望这会有所帮助 . :-)

  • 255

    步骤跟随
    1.打开 app.module.ts 文件 .
    .
    2.添加 import { FormsModule } from '@angular/forms';
    .
    3.将 FormsModule 添加到 imports 作为 imports: [ BrowserModule, FormsModule ],
    .

    最终结果将如下所示

    .....
    import { FormsModule } from '@angular/forms';
    .....
    @NgModule({
    .....
      imports: [   
         BrowserModule, FormsModule 
      ],
    .....
    })
    
  • 2

    首先从angular lib和NgModule导入FormsModule在导入中声明它

    import { FormsModule } from '@angular/forms';
        @NgModule({
          declarations: [
            AppComponent,
            ],
          imports: [
            BrowserModule,
            FormsModule
          ],
          providers: [],
          bootstrap: [AppComponent]
        })
    
  • 4

    您需要将@ angular / forms依赖项导入模块 .

    如果您使用的是npm,请安装依赖项:

    npm install @angular/forms --save
    

    将其导入您的模块:

    import {FormsModule} from '@angular/forms';
    @NgModule({
        imports: [.., FormsModule,..],
        declarations: [......],
        bootstrap: [......]
    })
    

    如果您使用SystemJs加载模块

    '@angular/forms': 'node_modules/@angular/forms/bundles/forms.umd.js',
    

    现在您可以使用[(ngModel)]两种方式进行数据绑定 .

  • 8

    您需要在@NgModule装饰器中导入FormsModule,而@NgModule存在于moduleName.module.ts文件中 .

    import { FormsModule } from '@angular/forms';
    @NgModule({
       imports: [
          BrowserModule,
          FormsModule
       ],
       declarations: [ AppComponent ],
       bootstrap: [ AppComponent ]
     })
    
  • 51
    import {FormControl,FormGroup} from '@angular/forms';
    
    import {FormsModule,ReactiveFormsModule} from '@angular/forms';
    

    您还应该添加缺少的那些 .

  • 4

    为了能够使用 'ngModule' ,需要将 'FormsModule' (来自 @angular/forms )添加到 AppModule 中的 import[] 数组中(默认情况下应该在CLI项目中) .

  • 2

    在Googling中找到此解决方案,更新您的@NgModule代码,如下所示:

    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 { }
    

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

  • 3

    您只需添加 FormsModule 并在 app.module.ts 文件中导入 FormsModule .

    import { FormsModule } from '@angular/forms';
    
    imports: [
        BrowserModule, FormsModule 
    ],
    

    只需在 app.module.ts 中添加以上两行即可 . 它工作正常 .

  • 0

    由于Angular 6中的某些原因,只是导入FormsModule并没有解决我的问题 . 最后解决我的问题的是添加

    import { CommonModule } from '@angular/common';
    
    @NgModule({
      imports: [CommonModule],
    })
    
    export class MyClass{
    }
    

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