无法获取React表单值

class MyForm extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      inputValue: ''
    };
  }

  handleChange(event) {
    this.setState({ inputValue: event.target.value });
  }

  handleSubmit(event) {
    event.preventDefault();
    console.log('Form submitted with value: ', this.state.inputValue);
  }

  render() {
    return (
      <form onSubmit={this.handleSubmit.bind(this)}>
        <input type="text" value={this.state.inputValue} onChange={this.handleChange.bind(this)} />
        <button type="submit">Submit</button>
      </form>
    );
  }
}

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

  handleSubmit(event) {
    event.preventDefault();
    console.log('Form submitted with value: ', this.inputRef.current.value);
  }

  render() {
    return (
      <form onSubmit={this.handleSubmit.bind(this)}>
        <input type="text" ref={this.inputRef} />
        <button type="submit">Submit</button>
      </form>
    );
  }
}