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react实现级联

2026-01-26 15:08:31React

实现级联选择器的基本思路

级联选择器通常用于处理具有层级关系的数据，例如省市区选择。React中可以通过状态管理和组件联动实现这一功能。

数据结构的组织

采用嵌套结构或扁平化结构存储级联数据。嵌套结构更适合展示父子关系：

const data = [
  {
    id: 1,
    name: '北京',
    children: [
      { id: 11, name: '海淀区' },
      { id: 12, name: '朝阳区' }
    ]
  }
]

状态管理方案

使用useState或useReducer管理当前选择的各级数据：

const [selectedValues, setSelectedValues] = useState({
  level1: null,
  level2: null,
  level3: null
});

组件联动实现

创建多个关联的选择器组件，下级选择器根据上级选择结果动态渲染：

function Cascader({ data }) {
  const [selected, setSelected] = useState({});

  const handleChange = (level, value) => {
    setSelected(prev => ({
      ...prev,
      [level]: value,
      // 清空下级选择
      ...Object.fromEntries(
        Object.keys(prev)
          .filter(key => parseInt(key.replace('level', '')) > parseInt(level.replace('level', '')))
          .map(key => [key, null])
      )
    }));
  };

  return (
    <div>
      <Select 
        options={data} 
        onChange={(value) => handleChange('level1', value)} 
      />

      {selected.level1 && (
        <Select
          options={data.find(item => item.id === selected.level1)?.children || []}
          onChange={(value) => handleChange('level2', value)}
        />
      )}
    </div>
  );
}

性能优化建议

对于大数据量的级联选择，可采用以下优化方案：

虚拟滚动技术处理长列表
异步加载下级数据
使用React.memo避免不必要的渲染

完整示例代码

import React, { useState } from 'react';

const Cascader = ({ data }) => {
  const [selected, setSelected] = useState({
    province: null,
    city: null,
    district: null
  });

  const handleProvinceChange = (value) => {
    setSelected({
      province: value,
      city: null,
      district: null
    });
  };

  const handleCityChange = (value) => {
    setSelected(prev => ({
      ...prev,
      city: value,
      district: null
    }));
  };

  const currentProvince = data.find(p => p.id === selected.province);
  const currentCity = currentProvince?.children?.find(c => c.id === selected.city);

  return (
    <div className="cascader">
      <select 
        value={selected.province || ''} 
        onChange={(e) => handleProvinceChange(e.target.value)}
      >
        <option value="">选择省份</option>
        {data.map(province => (
          <option key={province.id} value={province.id}>
            {province.name}
          </option>
        ))}
      </select>

      {selected.province && (
        <select
          value={selected.city || ''}
          onChange={(e) => handleCityChange(e.target.value)}
        >
          <option value="">选择城市</option>
          {currentProvince.children.map(city => (
            <option key={city.id} value={city.id}>
              {city.name}
            </option>
          ))}
        </select>
      )}

      {selected.city && (
        <select
          value={selected.district || ''}
          onChange={(e) => setSelected(prev => ({...prev, district: e.target.value}))}
        >
          <option value="">选择区县</option>
          {currentCity.children.map(district => (
            <option key={district.id} value={district.id}>
              {district.name}
            </option>
          ))}
        </select>
      )}
    </div>
  );
};