本文主要介绍了如何编写一个完整的Angular4 FormText 组件，分享给大家，也给自己留个笔记

组件定义

import { Component, Output, Input, forwardRef, EventEmitter} from '@angular/core';import {ControlValueAccessor, NG_VALUE_ACCESSOR} from '@angular/forms';@Component({ selector: 'form-text', template: ` <div > <label>{{label}}：</label> <input type="text" [(ngModel)]="value" placeholder="{{placeholder}}" > </div> `, providers: [ { provide:NG_VALUE_ACCESSOR, useExisting:forwardRef(()=>FormTextComponent), multi:true } ]})export class FormTextComponent implements ControlValueAccessor { @Input() label:string = ''; @Input() placeholder: string=''; @Output() onChange: EventEmitter<any> = new EventEmitter<any>(); public innerValue: any; public changeFn: Function = () => {}; get value(): any { return this.innerValue; }; set value(v: any) { if (v !== this.innerValue) { this.innerValue = v; this.changeFn(v); } } writeValue(value: any) { if (value !== this.innerValue) { this.innerValue = value; } } registerOnChange(fn: any) { this.changeFn = fn; } registerOnTouched(fn: any) { // }}

组件使用

<form-text [(ngModel)]="mobile" [placeholder]="placeholder" [label]="label"></form-text><p>{{mobile}}</p>

需要注意的点：

1.需要配置组件的providers
2.需要实现ControlValueAccessor接口

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。