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找一找教程网。
