Question

无法绑定到＆＃39; formGroup＆＃39;因为它不是“形式”的已知属性。

为什么会收到此错误消息？

请参阅我的http://www.ietf.org/rfc/rfc1738.txt了解实时示例。

文件app.module.ts：

import { NgModule } from '@angular/core';
import { BrowserModule }  from '@angular/platform-browser';
import { ReactiveFormsModule } from '@angular/forms';

import { AppComponent } from './app.component';
import { CustomInputComponent } from './custom-input.component';


@NgModule({
  imports: [
    BrowserModule, ReactiveFormsModule
  ],
  declarations: [
    AppComponent, CustomInputComponent
  ],
  providers: [

  ],
  bootstrap: [ AppComponent ]
})
export class AppModule { }

文件main.ts：

import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';

import { AppModule } from './app.module';

platformBrowserDynamic().bootstrapModule(AppModule);

文件app.component.ts：

import { Component, OnInit } from '@angular/core';
import { FormBuilder, FormGroup, Validators, AbstractControl } from '@angular/forms';

@Component({
  moduleId: module.id,
  selector: 'my-app',
  template: `
<h2>Testing Angular 2: custom form input</h2>

<form [formGroup]="form" (ngSubmit)="submit()">
  <custom-input [name]="city" [formControl]="city"></custom-input>
</form>
`
})
export class AppComponent implements OnInit {
  private form: FormGroup;
  private city: AbstractControl;

  constructor(private fb: FormBuilder) {}

  ngOnInit() {
    this.form = this.fb.group({
      'city': 'London'
    });
    this.city = this.form.controls['city']; 
  }

  submit() {
    let formValues = this.form.value;
    console.log('submit',JSON.stringify(formValues));
  }
}

文件custom-input.compontent.ts：

import { Component } from '@angular/core';
import { AbstractControl } from '@angular/forms';

@Component({
  moduleId: module.id,
  selector: 'custom-input',
  template: '<input [name]="name" [id]="name" [formControl]="formControl" type="text">'
})

export class CustomInputComponent {
  @Input() name: string;
  @Input() formControl: AbstractControl;

  constructor() {}
}

Answer 1

我开始构建一个新的Plunker，因为你似乎没有正确设置。我还修复了代码中的几个小问题

Plunker example

缺少的是，要用作表单控件的自定义元素需要实现ControlValueAccessor

无法绑定到＆＃39; formGroup＆＃39;

1 个答案: