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1.子组件调用父组件函数方法

//父组件
let Father=()=>{
    let getInfo=()=>{
        
    }
    return (
        <div>
            <Children 
                getInfo={getInfo}
            />
        </div>
    )
}

//子组件
let Children=(param)=>{
    return (
        <div>
            <span onClick={param.getInfo}>调用父组件函数</span>
        </div>
    )
}

2.父组件条用子组件函数方法

//父组件
//需要引入useRef
import {useRef} from 'react'
let Father=()=>{
    const childRef=useRef();
    let onClick=()=>{
        childRef.current.getInfo();
    }
    return (
        <div>
            <Children 
                ref={childRef}
            />
            <span onClick={onClick}>调用子组件函数</span>
        </div>
   )
}

//子组件 
//需要引入useImperativeHandle,forwardRef
import {useImperativeHandle,forwardRef} from 'react'
let Children=(ref)=>{
    useImperativeHandle(ref, () => ({
        getInfo:()=>{
            //需要处理的数据
        }
    }))
    return(
        <div></div>
    )
}
Children = forwardRef(Children);

3.子组件函数获取父组件的参数

1、封装的公共文件

// createContext.js文件
import { createContext } from "react";
const myContext = createContext(null);
export default myContext;

2、父组件

import React, { useState} from "react";
import Counter from './Counter'
import myContext from './createContext'

function App() {
  const [count, setCount] = useState(0);

  return (
    <div>
      {/* 提供器 */}
      <myContext.Provider value={count}>
        <Counter />
      </myContext.Provider>
    </div>
  );
}
export default App;

3、子组件

import React, { useContext} from 'react';
import myContext from './createContext'

// 关键代码
function Counter() {
    const count = useContext(myContext);  // 得到父组件传的值
    return (
        <div>
            <h4>我是子组件</h4>
            <p>这是父组件传过来的值：{count}</p>
        </div>
    )
}

export default Counter;