React 跨组件传值内置方法.

祖父

import React, { useState, createContext } from 'react'
import Pands from './Pands'

// 使用内置createContext导出数据
export const Context = createContext()

export default function App () {
  const [a, b] = useState(8)
  const handleClick = () => {
    b((a) => a + 1)
  }
  return (
    <Context.Provider
      value={
   
   {
        a,
        handleClick
      }}
    >
      <div>
        App
        <hr />
        <Pands></Pands>
      </div>
    </Context.Provider>
  )
}

父.一层或者多层传值.都可以.

import React from 'react'
import Chidren from './Chidren'
export default function Pands () {

  return (
    <div>
      Pands
      <hr />
      <Chidren></Chidren>
    </div>
  )
}

子

import React, { useContext } from 'react'
import { Context } from './App'


// 内置useContext接收数据
export default function Children () {
  const value = useContext(Context)
  return (
    <>
      Chidren
      <h3>{value.a}</h3>
      <button onClick={value.handleClick}>按钮</button>
    </>
  )
}