之前一直用的antd的Select组件，但在有些端并不适用，而原生的select样式修改不灵活，遂产生自己写一个组件的想法。观察select组件：

<select onChange={(value) => {this.value=value}} <option value='1'>man</option> <option value='0'>woman</option></select>

可以看出数据都是在option中，有值value和显示出来的数据一一对应。如果我们写一个select组件，那么应该有onChange方法，应该要访问到子元素，而且div是没有value这个属性的，所以option应该也是一个组件，有value属性。下面是我写的组件的用法：

import {MobileSelect, MobileOption} from '../../components/MobileSelect'; <MobileSelect disabled={isDisabled} value={data.clarity || ringResponse.clarity || 'Flawless'} style={{ width: '132px' }} onChange={(v) => this.changeDataValue('clarity', v)} > { (clarity || []).map((item, i) => { return ( <MobileOption key={i + ''} value={item.code}>{item.title}</MobileOption> ); }) } </MobileSelect>

可以看出其和一般的select组件用法差不多。效果如下：

下面是组件

import {observable} from 'mobx';import {observer} from 'mobx-react';import React from 'react';import {Icon} from 'antd';import './index.less';interface IProps { disabled?: boolean; onChange?: (value) => void; value?: string | number; style?: React.CSSProperties; className?: string;}@observerexport class MobileSelect extends React.Component<IProps> { @observable showOption = false; // 是否弹出下拉框 @observable value: any = ''; // 当前选中的value值 @observable text: any = ''; // 选中的value值对应的文本 @observable cell: any; // 组件的dom节点 componentDidMount(): void { // 获取选择框的ref，当在组件外点击时的时候收起下拉框 document.addEventListener('click', (e) => { if (this.cell && this.cell !== e.target && !this.cell.contains(e.target)) { this.showOption = false; } }, true); } componentWillReceiveProps(nextProps: Readonly<IProps>, nextContext: any): void { // 根据传入的value值，遍历children，找到对应值的展示文本 if (nextProps.value !== this.props.value || nextProps.children !== this.props.children) { React.Children.map(this.props.children, (child, index) => { if (nextProps.value === child.props.value) { this.text = child.props.children; } }); } } render(): React.ReactNode { const {children, value} = this.props; console.log(value); return ( <div className={'Mobile-Select ' + this.props.className} style={this.props.style} ref={(node) => this.cell = node} > <div className={'select-wrap'} onClick={() => { // 禁用不能弹出下拉框 if (!this.props.disabled) { this.showOption = !this.showOption; } }} > <Icon type='down' style={this.showOption ? {transform: 'rotate(180deg)'} : {transform: 'rotate(0deg)'}} className={'select-icon'}/> {this.text} </div> <div className={'option-wrap'} style={this.showOption ? {position: 'absolute'} : {display: 'none'}}> { React.Children.map(children, (child, index) => { // 设置选中option和未选中option的样式 let optionClassName = ''; if (this.props.value === child.props.value) { optionClassName = child.props.className ? child.props.className + ' option-item selected' : 'option-item selected'; } else { optionClassName = child.props.className + ' option-item'; } return ( <div onClick={() => { // 为了在父组件给子组件添加onClick事件，包裹了一层div // 有无onChange事件都能改变值 if (this.props.value && this.props.onChange) { this.props.onChange(child.props.value); } else { this.text = child.props.children; this.value = child.props.value; } console.log(this.value); this.showOption = !this.showOption; }} style={this.props.style} className={optionClassName} >{child}</div> ); }) } </div> </div> ); }}interface OptionProps { value?: string | number; className?: string; style?: React.CSSProperties;}export class MobileOption extends React.Component<OptionProps> { render(): React.ReactNode { const {children} = this.props; return ( <div style={this.props.style}> {children} </div> ); }}

下面是组件的样式

.Mobile-Select { display: inline-block; min-width: 100px; margin: 0 6px; .select-wrap { border: 1px solid #e0c0a2; border-radius: 4px; padding: 5px 11px; display: flex; flex-direction: row-reverse; justify-content: space-between; align-items: center; .select-icon { transition: .3s; float: right; } } .option-wrap { box-shadow: 0 0 5px #333; z-index: 1000; border-radius: 5px; .option-item { background-color: #fff; padding: 2px 11px; min-width: 100px; &.selected { background-color: #fbe6d0; } } }}

总的来说只实现了select的基本功能。有改进的地方请指点一二。

PS：React Select默认值选中问题

import React from "react";import { render } from "react-dom";class App extends React.Component { constructor(props) { super(props); this.state = { projects: [], value: "" }; } componentDidMount() { // 模拟ajax调用，成功之后把需要改变的默认值赋值给this.state.value setTimeout(() => { this.setState({ projects: [ { id: 1, name: "花生" }, { id: 2, name: "苹果" }, { id: 3, name: "杨桃" } ], value: 1 }); }, 3000); } handleClick() { this.setState({ projects: [ { id: 4, name: "水果" }, { id: 5, name: "西瓜" }, { id: 6, name: "哈哈哈" } ], value: 4 }); } handleChange = e => { this.setState({ value: e.target.value }); }; render() { let projects = this.state.projects; return ( <div> <button onClick={this.handleClick.bind(this)}>异步拉取数据</button> {} <select defaultValue="" value={this.state.value} onChange={this.handleChange} > {projects.length > 0 && projects.map((item, i) => { return ( <option key={i} value={item.id}> {item.name} </option> ); })} </select> </div> ); }}render(<App />, document.getElementById("root"));

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。