如何随时获取父组件中的子组件输入元素

// 子组件
class ChildComponent extends React.Component {
  constructor(props) {
    super(props);
    this.inputRef = React.createRef();
  }

  render() {
    return <input ref={this.inputRef} />;
  }
}

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

  handleClick = () => {
    const inputElement = this.childRef.current.inputRef.current;
    console.log(inputElement.value);
  };

  render() {
    return (
      <div>
        <ChildComponent ref={this.childRef} />
        <button onClick={this.handleClick}>获取子组件输入元素的值</button>
      </div>
    );
  }
}