React中refs的一些常见用法汇总

import React from "react";
// 父组件
export default class StringRef extends React.PureComponent {
  componentDidMount() {
    console.log("stringRefDom:", this.refs.stringRefDom);
    console.log("stringRefComp:", this.refs.stringRefComp);
  }
  render() {
    return (
      <div>
        {/*原生组件使用方式*/}
        <div ref={"stringRefDom"}>stringRefDom</div>
        {/*类组件使用方式*/}
        <StringRefComp ref={"stringRefComp"} />
      </div>
    );
  }
}
//类组件
class StringRefComp extends React.PureComponent {
  render() {
    return <div>StringRefComp</div>;
  }
}

import React from "react";
// 父组件
export default class CallbackRef extends React.PureComponent {
  constructor(props) {
    super(props);
    this.callbackRefDom = null;
    this.callbackRefComp = null;
  }
  componentDidMount() {
    console.log("callbackRefDom:", this.callbackRefDom);
    console.log("callbackRefComp:", this.callbackRefComp);
  }
  //回调函数
  setCallbackRefDom = (ref) => {
    this.callbackRefDom = ref;
  };
  setCallbackRefComp = (ref) => {
    this.callbackRefComp = ref;
  };
  //回调函数
  render() {
    return (
      <div>
        <div ref={this.setCallbackRefDom}>callbackRefDom</div>
        <CallbackRefComp ref={this.setCallbackRefComp} />
      </div>
    );
  }
}

//类组件
class CallbackRefComp extends React.PureComponent {
  render() {
    return <div>callbackRefComp</div>;
  }
}

import React from "react";
// 父组件
export default class CreateRef extends React.PureComponent {
  constructor(props) {
    super(props);
    this.createRefDom = React.createRef();
    this.createRefComp = React.createRef();
  }
  componentDidMount() {
    console.log("createRefDom:", this.createRefDom.current);
    console.log("createRefComp:", this.createRefComp.current);
  }
  render() {
    return (
      <div>
        <div ref={this.createRefDom}>createRefDom</div>
        <CreateRefComp ref={this.createRefComp} />
      </div>
    );
  }
}
//类组件
class CreateRefComp extends React.PureComponent {
  render() {
    return <div>CreateRefComp</div>;
  }
}

import React, { useEffect } from "react";
// 父组件
const UseRef = React.memo(() => {
  // // 同样可以用
  // const createRefDom = React.createRef();
  // const createRefComp = React.createRef();
  const createRefDom = React.useRef();
  const createRefComp = React.useRef();
  useEffect(() => {
    console.log("useRefDom:", createRefDom.current);
    console.log("useRefComp:", createRefComp.current);
  }, []);
  return (
    <div>
      <div ref={createRefDom}>useRefDom</div>
      <UseRefComp ref={createRefComp} />
    </div>
  );
});

export default UseRef;

//类组件
class UseRefComp extends React.PureComponent {
  render() {
    return <div>useRefComp</div>;
  }
}

import React, { useEffect, useImperativeHandle } from "react";

// 父组件
const ForwardRef = React.memo(() => {
  const createRefComp = React.useRef();
  const createRefCompMethod = React.useRef();

  useEffect(() => {
    console.log("useRefComp:", createRefComp.current);
    console.log("createRefCompMethod:", createRefCompMethod.current);
    createRefComp.current.reload();
  }, []);
  return (
    <div>
      <ForwardRefFunc ref={createRefComp} />
    </div>
  );
});

export default ForwardRef;

const RefFunc = React.forwardRef((props, ref) => {
  const [name, setName] = React.useState(null);
  const reload = () => {
    console.log("reload");
    setTimeout(() => {
      setName("ForwardRefFunc");
    }, 3000);
  };
  //useImperativeHandle 可以让你在使用 ref 时自定义暴露给父组件的实例值
  useImperativeHandle(ref, () => {
    return {
      reload: reload,
    };
  });
  return <div ref={ref}>ForwardRefFunc {name}</div>;
});
const ForwardRefFunc = React.memo(RefFunc);