网站如何做分站系统网站建设与运营的课程总结

 1、效果

是你要的效果，咱们继续往下看，搜索面板实现省市区下拉，原本有antd的Cascader组件，但是级联组件必须选到子节点，不能只选省，满足不了页面的需求

2、环境准备

1、react18

2、antd 4+

3、功能实现

原理：封装一个受控组件，该组件就是两select基本组件

1、首先，导入需要的组件：

import { Select, Space, Tag } from 'antd';

 2、定义2个状态变量来存储选中省和市的下拉枚举

  const [firstOptions, setFirstOptions] = useState<any>([]);const [secondOptions, setSecondOptions] = useState<any>([]);

 3、组件可接收的props子属性 如下：

•  options: 省市级联数据
•  value: 已选中的值
•  width：slect框的宽度
•  firstPlaceholder 第一个select框的placeholder
• secondPlaceholder第二个select框的placeholder
•  onChange： 选中的值发生变化时回调

 4、创建handleFirstChange函数来处理第一个select框的change事件，更新第二个select框的下拉项和值

  // 第一个select生变化const handleFirstChange = (data: any) => {if (!isEmpty(data) && data.value) {let insertIndex = (options || []).findIndex((item: any) => {return item?.value === data?.value;});setSecondOptions(options?.[insertIndex]?.children || []);onChange({ first: [data] });} else {setSecondOptions([]);onChange(null);}};

 5、创建onSecondChange 函数来处理第二个select框的change事件，将选中的值回传给父组件

  // 第二个select发生变化const onSecondChange = (data: any) => {if (!isEmpty(value) && value.first) {if (!isEmpty(data)) {onChange({...value,second: mode === 'multiple' ? (data || []).filter((item: any) => !isNil(item?.label)) : [data],});} else {onChange({ first: value.first, second: null });}} else {onChange(null);}};

 6、最后，使用2个select组件渲染，并将选中状态和change事件绑定到对应的属性上：

return (<><Space wrap={false} direction="horizontal" size={12}><SelectdefaultValue={firstOptions[0]}style={{ width: width }}onChange={handleFirstChange}placeholder={firstPlaceholder || '请选择'}value={value?.first}options={firstOptions}labelInValueallowClear/><Selectstyle={{ width: width }}value={value?.second || []}onChange={onSecondChange}placeholder={secondPlaceholder || '请选择'}options={secondOptions}{...mode === "multiple" ? { mode: "multiple", maxTagCount: 'responsive', tagRender: tagRender } : {}}labelInValueallowClear/></Space></>
)

 7、完整代码如下：

import { Select, Space, Tag } from 'antd';
import clsx from 'clsx';
import { isEmpty, isNil } from 'lodash';
import { useEffect, useState } from 'react';
import './index.less';const MultipleCascaderSelect = (props: any) => {const {options,value,onChange,width = 160,firstPlaceholder,secondPlaceholder,mode = 'multiple'} = props;const [firstOptions, setFirstOptions] = useState<any>([]);const [secondOptions, setSecondOptions] = useState<any>();useEffect(() => {setFirstOptions(options || []);if (Array.isArray(value?.first) && value.first.length) {let findIndex = (options || []).findIndex((item: any) => {return item.value === value.first?.[0].value;});setSecondOptions(options[findIndex]?.children || []);} else {setSecondOptions([]);}}, [options, value]);// 第一个select生变化const handleFirstChange = (data: any) => {if (!isEmpty(data) && data.value) {let insertIndex = (options || []).findIndex((item: any) => {return item?.value === data?.value;});setSecondOptions(options?.[insertIndex]?.children || []);onChange({ first: [data] });} else {setSecondOptions([]);onChange(null);}};// 第二个select发生变化const onSecondChange = (data: any) => {if (!isEmpty(value) && value.first) {if (!isEmpty(data)) {onChange({...value,second: mode === 'multiple' ? (data || []).filter((item: any) => !isNil(item?.label)) : [data],});} else {onChange({ first: value.first, second: null });}} else {onChange(null);}};const tagRender = ({ label, closable, onClose }: any) => {const isLongTag = `${label}`.length > 4;return (<Tagcolor={label.props?.color}closable={closable}onClose={onClose}className={clsx(['text-sky-400 bg-sky-400/10 text-sm font-normal leading-5',// 'border border-solid border-sky-400/50','max-w-[110px] border-none',// 'whitespace-nowrap text-ellipsis overflow-hidden'])}><span>{isLongTag ? `${label.slice(0, 4)}...` : label}</span>{/* {isLongTag ? (<Tooltiptitle={label}key={label}rootClassName={clsx('toolTipCard')}placement="top"><span>{label.slice(0, 4)}...</span></Tooltip>) : (<span>{label}</span>)} */}</Tag>);};return (<><Space wrap={false} direction="horizontal" size={12}><SelectdefaultValue={firstOptions[0]}style={{ width: width }}onChange={handleFirstChange}placeholder={firstPlaceholder || '请选择'}value={value?.first}options={firstOptions}labelInValueallowClear/><Selectstyle={{ width: width }}value={value?.second || []}onChange={onSecondChange}placeholder={secondPlaceholder || '请选择'}options={secondOptions}{...mode === "multiple" ? { mode: "multiple", maxTagCount: 'responsive', tagRender: tagRender } : {}}labelInValueallowClear/></Space></>);
};export default MultipleCascaderSelect;

组件调用

 <MultipleCascaderSelectwidth={162}options={enumData|| []}firstPlaceholder="请选择"secondPlaceholder="请选择"/>