Question

我有这样的简单自定义输入组件，

import {Component, Provider, forwardRef} from "@angular/core";
import {ControlValueAccessor, NG_VALUE_ACCESSOR} from "@angular/forms";

const noop = () => {};

const CUSTOM_INPUT_CONTROL_VALUE_ACCESSOR: any = {
  provide: NG_VALUE_ACCESSOR,
  useExisting: forwardRef(() => CustomInputComponent),
  multi: true
};

@Component({
  selector: 'custom-input',
  template: `

          <input class="form-control" 
                 [(ngModel)]="value" name="somename"
                 (blur)="onTouched()">

  `,
  providers: [CUSTOM_INPUT_CONTROL_VALUE_ACCESSOR]
})
export class CustomInputComponent implements ControlValueAccessor{

  //The internal data model
  private _value: any = '';

  //Placeholders for the callbacks
  private _onTouchedCallback: () => void = noop;

  private _onChangeCallback: (_:any) => void = noop;

  //get accessor
  get value(): any { return this._value; };

  //set accessor including call the onchange callback
  set value(v: any) {
    if (v !== this._value) {
      this._value = v;
      this._onChangeCallback(v);
    }
  }

  //Set touched on blur
  onTouched(){
    this._onTouchedCallback();
  }

  //From ControlValueAccessor interface
  writeValue(value: any) {
    this._value = value;
  }

  //From ControlValueAccessor interface
  registerOnChange(fn: any) {
    this._onChangeCallback = fn;
  }

  //From ControlValueAccessor interface
  registerOnTouched(fn: any) {
    this._onTouchedCallback = fn;
  }

}

我有这样的app模块，

/**
 * Created by amare on 8/15/16.
 */
import { NgModule }                     from '@angular/core';
import { BrowserModule }                from '@angular/platform-browser';
import { ReactiveFormsModule, FormsModule }          from '@angular/forms';
import { AppComponent }                 from './app/app.component';
import {CustomInputComponent} from "./app/shared/custom.input.component";
import {RouterModule} from "@angular/router";
@NgModule({
  imports: [ BrowserModule, ReactiveFormsModule, FormsModule, RouterModule ],
  declarations: [ AppComponent, CustomInputComponent],
  bootstrap: [ AppComponent ]
})
export class AppModule {  
}

和主要

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

platformBrowserDynamic().bootstrapModule(AppModule);

我已经在我的一个组件中使用了我的自定义输入，如下所示，但是我得到'没有用于具有未指定名称属性的表单控件的值访问器'。

<custom-input name="firstName" [(ngModel)]="firstName"></custom-input>

，app.component看起来像这样

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

@Component({
  moduleId: module.id,
  selector: 'app-root',
  templateUrl: 'app.component.html',
  styleUrls: ['app.component.css']
})
export class AppComponent {
  title = 'app works!';

  firstName: string;
}

Answer 1

将ngDefaultControl添加到主机中的自定义输入组件解决了问题，感谢@danieleds

Answer 2

将ngDefaultControl添加到自定义输入组件。这增加了双向数据绑定，除非你做一些独特的事情，否则你不应该实现值访问器方法。

<custom-input name="firstName" [(ngModel)]="firstName" ngDefaultControl></custom-input>

Answer 3

将ngDefaultControl添加到您的输入中。例如

<inline-editor type="textarea" [(ngModel)]="editableTextArea" (onSave)="saveEditable($event)" value="valor" ngDefaultControl> </inline-editor>

然后import { FORM_DIRECTIVES } from '@angular/common';

最后指令：[FORM_DIRECTIVES]

这将有效:)感谢上述评论

Answer 4

我在自己的[(ngModel)]标签上放了<option>而不是<select>

是的...这会导致这种情况。

Answer 5

在出现这种情况的另一种情况下，我在最近重建和简化的自定义组件上指定了[(ngModel)]，并且该组件的新版本仅将ngModel作为常规输入变量发出。

这还不够-输入变量必须重命名为ngModel以外的名称，否则组件必须实现ControlValueAccessor接口（see the docs for details）。一旦一个完成，您将不再收到此错误。

angular2 rc.5自定义输入，没有用于具有未指定名称的表单控件的值访问器

5 个答案: