将钩子转换为 Class 但出现错误

Question

我想将 React hooks 组件转换为 class 组件，但出现错误。

HOOKS

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

const App = () => {
  const refValt = useRef(null);

  const myfuncValt = () => {
    console.log("222222222222222222222");
  };


  useEffect(() => {
    setTimeout(() => {
      refValt.current.click();
    }, 5000); //miliseconds
  }, []);

  return (
    <div>
      <div ref={refValt} onClick={myfuncValt}>Valt</div>
    </div>
  );
};

export default App;

CLASS

import React  from "react";

const myfuncValt = () => {
  console.log("222222222222222222222");
};

class App extends React.Component {
  constructor(props) {
    super(props);
    const refValt = React.createRef(null);
  }

  componentDidMount() {
    setTimeout(() => {
      this.refValt.current.click();
    }, 5000);
  }

  render() {
    return (
      <div>
        <div ref={this.refValt} onClick={myfuncValt}>
          Valt
        </div>
      </div>
    );
  }
}

export default App;

我得到这个错误=

我试试this.refValt.click();但它不起作用。

实际上我怀疑 createref 和 useref 之间的区别。

Answer 1

这个：

const refValt = React.createRef(null);

...需要这样：

this.refValt = React.createRef(null);

将钩子转换为 Class 但出现错误

React Convert Hooks To Class But Get Error

javascript

class

jsx

reactjs

react-hooks