1. utils下的context.js 

import React ,{ createContext} from "react" //createContext 是创建一个上下文对象
export const dateContext= createContext({}) // 创建了一个上下文对象
export const {Provider,Consumer} = dateContext

2.爷爷组件 

import {Provider} from "../utils/context"<Provider value={obj}><Appson sendfn={sendfn}></Appson></Provider>

3.孙子组件 

 import React from 'react'
import {useContext} from "react" // 
import {dateContext} from "../utils/context"
function Appgrand() {let contextValue = useContext(dateContext)console.log(contextValue,111);return (<div> 我是爷爷组件传递来的数据{contextValue.name}</div>)
}export default Appgrand