我正在尝试在react的下拉菜单中获取属性的值

import React, { Component } from 'react';

class Dropdown extends Component {
  constructor(props) {
    super(props);
    this.state = {
      selectedValue: '' // 初始化属性值变量
    };
  }

  handleDropdownChange = (event) => {
    this.setState({ selectedValue: event.target.value }); // 更新属性值变量
  }

  render() {
    return (
      <select value={this.state.selectedValue} onChange={this.handleDropdownChange}>
        <option value="value1">选项1</option>
        <option value="value2">选项2</option>
        <option value="value3">选项3</option>
      </select>
    );
  }
}