如何强制重新呈现嵌套的组件

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

  const handleButtonClick = () => {
    setCount(count + 1);
  };

  return (
    <div>
      <button onClick={handleButtonClick}>重新呈现子组件</button>
      <ChildComponent key={count} />
    </div>
  );
}

class ParentComponent extends React.Component {
  constructor(props) {
    super(props);
    this.childRef = React.createRef();
  }

  handleButtonClick = () => {
    this.childRef.current.forceUpdate();
  };

  render() {
    return (
      <div>
        <button onClick={this.handleButtonClick}>重新呈现子组件</button>
        <ChildComponent ref={this.childRef} />
      </div>
    );
  }
}