Python tkinter调用askopenfilename后进程无法正常退出

本人并非专业程序员，问题标题表述可能存在偏差。
开发了一款处理IFC文件的Python程序：

• IFC是建筑行业常用文件格式，存储3D图纸的几何信息及图纸内对象的关联数据
• 程序运行流程：启动后先选择目标IFC文件，之后弹出交互对话框，支持用户输入GUID（对象标识符），检索IFC文件中与该GUID对应对象关联的全部信息，最终将检索结果打印到命令提示符窗口

使用tkinter的askopenfilename函数实现可视化文件选择时，关闭后续弹出的GUID查询对话框后，程序进程仍处于活跃/循环状态无法自动退出，必须按下Ctrl+C强制终止进程。

#imports to search for files
import os

# imports tkinter for selection purposes, so that one can select the files instead of reading in them automaticall from a directory
import tkinter as tk
from tkinter.filedialog import askopenfilename

#importing the counter to counte the occurences in a list
from collections import Counter

#importing regex functionality to check values
import re

#this is the numbering, for example #433, #4781 etc, that we either want to look for or change - now it looks for up to a number of length 7
regexIFCnumbers = '#\d{1,7}'


tk.Tk().withdraw() # we don't want a full GUI, so keep the root window from appearing
file1 = askopenfilename(initialdir=os.getcwd()) # show an "Open" dialog box and return the path to the selected file - this in the current directory where we'll start looking

file1Name = (os.path.basename(file1)) #only the file's name
    
#read files
def readFile(file):
    x = []
    f = open(file, 'r') 
    x = f.readlines()
    f.close()
    return(x)

x1 = readFile(file1)

#checks the GUIDs
def checkGUID(GUID, IFC):
    A = []
    for row in IFC:
        if GUID in row:
            #print(re.findall(regexIFCnumbers, row))
            
            A.extend(re.findall(regexIFCnumbers, row))
            return(A)

#the numbering is not perfectly ordered and varies in some places, so need to index it all to find the correct lines
def indexIFC(IFC):
    A = []
    for index, row in enumerate(IFC):
        if re.findall('^#', row): #starts with a hash #
            B = re.findall(r'\#\w+', row)[0]
            A.append([B, index])
            
    return(A)


def recurseThrough(inputList, IFC, checkedList, fullList, indexednumbersList):
    for item in inputList:
        for hashvalueList in indexednumbersList:
            if item == hashvalueList[0]:
                positionInIFC = hashvalueList[1]

        if re.search('^'+item, IFC[positionInIFC]) and item not in checkedList: #if the row begins with the number item in the list
            checkedList.append(item)
            fullList.append(IFC[positionInIFC])
            recurseThrough(re.findall(regexIFCnumbers, IFC[positionInIFC])[1:], IFC, checkedList, fullList, indexednumbersList) #recurses through the next list
    return(fullList)
    

from os import system, name
 
def clear():
    if name == 'nt':
        _ = system('cls')

def runTheGUIDCheck(setValue):
    inputValue = str(setValue)
    print(inputValue)
    clear()
    
    try:
        B1 = checkGUID(inputValue, x1) #This returns a list with for example [#122, #5, #7889]

        checkedList = [] #the list of already checked items
        fullList = []

        indexedIFClist1 = indexIFC(x1)

        #run the function with the initial input, sending in empty array as well as they should be empty/none at the start
        outList1 = recurseThrough(B1, x1, [], [], indexedIFClist1)

        for index, item in enumerate(outList1):
            print(index, item.strip())
        
        return None
    
    except:
        print("inserted GUID not found or didn't work")
        

        
#dialog
dialog = tk.Tk()

dialog.geometry('500x200')

t1 = tk.Label(dialog, text = 'Check GUID')
t1.grid(row = 0, column = 0, sticky = 'w')

testGUIDAttributes = tk.Entry(dialog, width = 40)
testGUIDAttributes.grid(row = 0, column = 1, columnspan = 50)

button = tk.Button(dialog, text='Run GUID', command = lambda: runTheGUIDCheck(testGUIDAttributes.get()))
button.grid(row = 5, column = 0, sticky = 'w')

dialog.mainloop()

• 测试操作：移除askopenfilename调用，直接硬编码文件路径：

file1 = 'thefile.ifc'

替换原代码中文件选择段：

tk.Tk().withdraw() # we don't want a full GUI, so keep the root window from appearing
file1 = askopenfilename(initialdir=os.getcwd()) # show an "Open" dialog box and return the path to the selected file - this in the current directory where we'll start looking

• 测试结果：进程无法退出的问题消失，关闭GUID查询对话框后，命令提示符窗口可正常接收新指令，进程自动结束。

代码中创建了两个独立的Tk根窗口实例：

1. 执行tk.Tk().withdraw()时生成第一个隐藏的根窗口，用于承载文件选择对话框，该实例没有被手动销毁，后台始终运行事件循环
2. 后续创建GUID对话框时执行dialog = tk.Tk()，生成第二个独立的根窗口
   关闭GUID对话框时仅销毁第二个Tk实例，第一个隐藏的根窗口仍在后台运行，因此进程不会自动退出。硬编码文件路径时没有创建第一个隐藏Tk实例，无残留事件循环，因此进程可正常退出。

Tkinter程序全程只能保留一个Tk根窗口实例，禁止重复创建：

1. 程序启动时先初始化唯一的根窗口，隐藏后用于弹出文件选择框
2. GUID对话框不要新建tk.Tk()实例，使用Toplevel创建依附于根窗口的子窗口
3. 绑定对话框关闭事件，触发时直接销毁唯一的根窗口，终止所有事件循环

核心修改代码参考：

# 初始化唯一的Tk根实例，全局复用
root = tk.Tk()
root.withdraw() # 初始隐藏，用于弹出文件选择对话框
file1 = askopenfilename(initialdir=os.getcwd())

# 增加空路径判断，避免用户点取消后读文件报错
if not file1:
    exit()

# --- 中间的文件读取、自定义函数部分无需修改 ---

# GUID对话框使用Toplevel创建子窗口，不要新建tk.Tk()
dialog = tk.Toplevel(root)
dialog.geometry('500x200')

# 绑定窗口关闭事件，关闭时销毁根实例，彻底退出程序
def on_dialog_close():
    root.destroy()
dialog.protocol("WM_DELETE_WINDOW", on_dialog_close)

# --- 原有标签、输入框、按钮的布局代码无需修改 ---

# 启动根窗口的事件循环
root.mainloop()

补充优化建议：原代码的文件读取、GUID检索逻辑缺少异常捕获，建议补充文件不存在、GUID无匹配结果的分支提示，避免程序无响应或抛出非预期错误。

内容的提问来源于stack exchange，提问作者user2703642