如何在React中使用Material-UI在onFocus事件上的Textfield中选择文本的一部分？

class App extends React.Component {
  handleFocus = event => {
    event.preventDefault();
    const { target } = event;
    const extensionStarts = target.value.lastIndexOf('.');
    target.focus();
    target.setSelectionRange(0, extensionStarts);
  }
  
  render(){
    return (
      <input
        value={'myfile.doc'}
        onFocus={this.handleFocus}
      />
    )
  }
}

ReactDOM.render(<App />, document.getElementById('root'));

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id="root"></div>