React通過ref獲取子組件的數(shù)據(jù)和方法
父組件
1) ref必須傳值, 否則childRef拿不到子組件的數(shù)據(jù)和方法
注意: 不一定使用app組件, 其他的任何父組件都可以
import "./App.css"; import React, { useEffect, useRef } from "react"; import RefToGetChild from "./components/RefToGetChild"; import _ from 'lodash'; const App: React.FC = () => { const childRef = useRef<any>(null); useEffect(() => { console.log(_.get(childRef, 'current')); }, [_.get(childRef, 'current')]); return ( <div> <RefToGetChild ref={childRef} message={"子組件: say hello"} /> <button onClick={() => { const child = _.get(childRef, 'current'); const buttonDom = child.buttonRef.current buttonDom?.click(); }}>父組件: trigger child button</button> <button onClick={() => { const child = _.get(childRef, 'current'); child?.onTest(); }}>父組件: 使用子組件的onTest方法</button> <div>父組件: 子組件的data {JSON.stringify(_.get(childRef, 'current.data'))}</div> </div> ); }; export default App;
子組件
1) forwardRef作用: 封裝組件, 直接將ref參數(shù)加在props后面(也可以不使用, 自己props定義一下ref需要傳參, 父組件一樣傳ref就行)
2) useImperativeHandle作用和vue3的defineExpose一樣, 存儲需要暴露給父組件讓其獲取的數(shù)據(jù)和函數(shù)
import { forwardRef, useEffect, useImperativeHandle, useRef, useState, } from "react"; const RefToGetChild = forwardRef((props:{message:string;}, ref) => { const [data, setData] = useState({}); const buttonRef = useRef(null); useEffect(() => { setTimeout(() => { const obj = { a: 1, b: 2, c: 3, d: Array.from({ length: 10 }, (_, i) => ({ id: i })), }; setData(obj); }, 1000); }, []); const sayHello = () => { console.log("hello"); }; const onTest = () => { console.log('test') } useImperativeHandle(ref, () => ({ data, buttonRef, onTest, })); return ( <div> <button ref={buttonRef} onClick={sayHello}> {props.message} </button> </div> ); }); export default RefToGetChild
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