如何将状态向下传递给子组件的处理程序？

Question

GeoJson 组件有一个调用处理程序的函数 onEachFeature，在本例中是 createPopup.

<GeoJSON data={covidGeoJSON} onEachFeature={createPopup}></GeoJSON>

在处理程序中 createPopup 如何访问在 CovidMap 组件中定义的状态？

import React, { useState } from 'react'
import { MapContainer, GeoJSON } from 'react-leaflet'
import 'leaflet/dist/leaflet.css'



CovidMap = ({ covidGeoJSON, styles }) => {

    const showCords = (e) => {
        console.log(e.latlng);
    }

    const createPopup = (state, layer) => {
        layer.on({
            mouseover: showCords,
        });
        layer.bindPopup(state.properties.NAME);
    }

    const [range, setRange] = useState([]);

    return (
        <div>
            <MapContainer style={{ height: '90vh', width: '100vw' }} center={[39.162497380360634, -94.83672007881789]} zoom={5}>
                <GeoJSON data={covidGeoJSON} onEachFeature={createPopup}></GeoJSON>
            </MapContainer>
        </div>
    )
}

export default CovidMap

Answer 1

您应该可以参考 createPopup 中的状态。使用 useState 挂钩在 CovidMap 中创建和使用状态变量：

const CovidMap = () => {

    ...
    const [properties, setProperties] = useState({}); // Defined BEFORE handler
    const [layer, setLayer] = useState({}); // Defined BEFORE handler

    const createPopup = () => {
        layer.on({
            mouseover: showCords,
        });
        layer.bindPopup(properties.NAME);
    }
    ...
}

如何将状态向下传递给子组件的处理程序？

How to pass state down to child component's handler?

javascript

reactjs

react-hooks

leaflet

react-leaflet