React:未定义this.state

class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = { count: 0 };
    this.handleClick = this.handleClick.bind(this);
  }

  handleClick() {
    console.log(this.state.count); // 正确输出状态
  }

  render() {
    return <button onClick={this.handleClick}>Click me</button>;
  }
}

class MyComponent extends React.Component {
  state = { count: 0 };

  handleClick = () => {
    console.log(this.state.count); // 正确输出状态
  }

  render() {
    return <button onClick={this.handleClick}>Click me</button>;
  }
}

import React, { useState } from 'react';

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

  const handleClick = () => {
    console.log(count); // 正确输出状态
  };

  return <button onClick={handleClick}>Click me</button>;
}