如何在getfielddecorator antd中动态改变initialValue？

import { Form, Input } from 'antd';

class MyForm extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      initialValue: '初始值',
    };
  }

  handleChangeInitialValue = () => {
    this.setState({ initialValue: '新的初始值' });
  }

  render() {
    const { getFieldDecorator } = this.props.form;
    const { initialValue } = this.state;

    return (
      <Form>
        <Form.Item>
          {getFieldDecorator('fieldName', {
            initialValue: initialValue,
          })(
            <Input />
          )}
        </Form.Item>
        <button onClick={this.handleChangeInitialValue}>改变初始值</button>
      </Form>
    );
  }
}

const WrappedForm = Form.create()(MyForm);