App.js的代码

06是函数组件

07是类组件

import React, { useEffect, useRef } from 'react';
import LearnFunction06 from './LearnFunction06'; //  函数组件和类组件的ref使用方式
import LearnFunction07 from './LearnFunction07'; //  函数组件和类组件的ref使用方式
export default function BoxReact() {

  const learnRef = useRef(null)
  const classRef = useRef(null)
  useEffect(() => {
    console.log(learnRef.current);
    console.log(classRef.current);
  }, [])
  return (
    <div>
      <LearnFunction06 ref={learnRef}></LearnFunction06>
      <LearnFunction07 ref={classRef}></LearnFunction07>
    </div>
  )
}

06的代码

import React, { forwardRef } from 'react'

export default forwardRef(function LearnFunction06(props, ref) {
    return (
        <div ref={ref}> LearnFunction06</div>
    )
})

正常函数组件是没有ref的,需要通过forwardRef来修饰组件才能产生ref

07的代码

import React, { Component } from 'react'

export default class LearnFunction07 extends Component {
  render() {
    return (
      <div>LearnFunction07</div>
    )
  }
}

效果图

这样都可以拿到ref啦