如何从连接到数据库的组合框中删除项目并自动刷新？

import mysql.connector
from tkinter import *

# 建立数据库连接
conn = mysql.connector.connect(
    host="数据库主机地址",
    user="用户名",
    password="密码",
    database="数据库名"
)

# 查询数据库并获取项目列表
def get_items():
    cursor = conn.cursor()
    cursor.execute("SELECT item_name FROM items")
    items = cursor.fetchall()
    cursor.close()
    return items

# 删除项目并刷新组合框
def delete_item():
    selected_item = combo.get()
    cursor = conn.cursor()
    cursor.execute("DELETE FROM items WHERE item_name = %s", (selected_item,))
    conn.commit()
    cursor.close()
    refresh_combo()

# 刷新组合框
def refresh_combo():
    combo['values'] = get_items()

# 创建GUI窗口
window = Tk()

# 创建组合框
combo = ttk.Combobox(window)
combo['values'] = get_items()
combo.pack()

# 创建删除按钮
delete_button = Button(window, text="删除", command=delete_item)
delete_button.pack()

# 运行窗口主循环
window.mainloop()

# 关闭数据库连接
conn.close()