如何使用Riverpod Notifier创建drowdownbutton按钮？

dependencies:
  flutter:
    sdk: flutter
  riverpod: ^1.0.0

import 'package:flutter/material.dart';

class DropdownState extends ChangeNotifier {
  String selectedValue = 'Option 1';

  void updateSelectedValue(String value) {
    selectedValue = value;
    notifyListeners();
  }
}

import 'package:flutter/material.dart';
import 'package:riverpod/riverpod.dart';

class MyPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('DropdownButton Example'),
      ),
      body: Center(
        child: Consumer(
          builder: (context, watch, _) {
            final dropdownState = watch(dropdownProvider);
            return DropdownButton<String>(
              value: dropdownState.selectedValue,
              onChanged: (newValue) {
                dropdownState.updateSelectedValue(newValue);
              },
              items: <String>['Option 1', 'Option 2', 'Option 3']
                  .map<DropdownMenuItem<String>>((String value) {
                return DropdownMenuItem<String>(
                  value: value,
                  child: Text(value),
                );
              }).toList(),
            );
          },
        ),
      ),
    );
  }
}

final dropdownProvider = ChangeNotifierProvider((ref) => DropdownState());

import 'package:flutter/material.dart';
import 'package:riverpod/riverpod.dart';

void main() {
  runApp(
    ProviderScope(
      child: MyApp(),
    ),
  );
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Riverpod DropdownButton Example',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyPage(),
    );
  }
}