为何Tkinter拖拽组件代码在CustomTkinter中失效？如何修复？

我有两段实现标签拖拽排序的代码，核心逻辑完全一致，唯一区别是一段基于原生Tkinter，另一段基于CustomTkinter。Tkinter版本运行正常，但CustomTkinter版本的拖拽功能完全失效。我已在CustomTkinter代码中用#this changed注释标注了与Tkinter版本的差异点，需要找到修复方法。

Tkinter版本代码 #

import tkinter

def changeOrder(widget1, widget2, initial):
    target = widget1.grid_info()
    widget1.grid(row=initial['row'], column=initial['column'])
    widget2.grid(row=target['row'], column=target['column'])

def on_click(event):
    widget = event.widget
    print(widget)
    if isinstance(widget, tkinter.Label):
        start = (event.x, event.y)
        grid_info = widget.grid_info()
        widget.bind("<B1-Motion>", lambda event: drag_motion(event, widget, start))
        widget.bind("<ButtonRelease-1>", lambda event: drag_release(event, widget, grid_info))
    else:
        root.unbind("<ButtonRelease-1>")

def drag_motion(event, widget, start):
    x = widget.winfo_x() + event.x - start[0]
    y = widget.winfo_y() + event.y - start[1]
    widget.lift()
    widget.place(x=x, y=y)

def drag_release(event, widget, grid_info):
    widget.lower()
    x, y = root.winfo_pointerxy()
    target_widget = root.winfo_containing(x, y)
    if isinstance(target_widget, tkinter.Label): 
        changeOrder(target_widget, widget, grid_info)
    else:
        widget.grid(row=grid_info['row'], column=grid_info['column'])

root = tkinter.Tk()
_entry = {}
rows = 3
columns = 2
for row in range(rows):
    for column in range(columns):
        index = (row, column)
        myTextLabel1 = tkinter.Label(root, text="Label 1", bg='yellow')
        myTextLabel1.grid(row=row, column=column, padx=5, pady=5)
        _entry[index] = myTextLabel1

_entry[index].configure(bg='red')

root.bind("<Button-1>", on_click)

root.mainloop()

CustomTkinter版本原代码（拖拽失效） #

# WITH CUSTOMTKINTER
import customtkinter

def changeOrder(widget1, widget2, initial):
    target = widget1.grid_info()
    widget1.grid(row=initial['row'], column=initial['column'])
    widget2.grid(row=target['row'], column=target['column'])

def on_click(event):
    widget = event.widget
    print(widget)
    if isinstance(widget, customtkinter.CTkLabel): #this changed
        start = (event.x, event.y)
        grid_info = widget.grid_info()
        widget.bind("<B1-Motion>", lambda event: drag_motion(event, widget, start))
        widget.bind("<ButtonRelease-1>", lambda event: drag_release(event, widget, grid_info))
    else:
        root.unbind("<ButtonRelease-1>")

def drag_motion(event, widget, start):
    x = widget.winfo_x() + event.x - start[0]
    y = widget.winfo_y() + event.y - start[1]
    widget.lift()
    widget.place(x=x, y=y)

def drag_release(event, widget, grid_info):
    widget.lower()
    x, y = root.winfo_pointerxy()
    target_widget = root.winfo_containing(x, y)
    if isinstance(target_widget, customtkinter.CTkLabel): #this changed
        changeOrder(target_widget, widget, grid_info)
    else:
        widget.grid(row=grid_info['row'], column=grid_info['column'])

root = customtkinter.CTk()
_entry = {}
rows = 3
columns = 2
for row in range(rows):
    for column in range(columns):
        index = (row, column)
        myTextLabel1 = customtkinter.CTkLabel(root, text="Label 1", bg_color='yellow') #this changed
        myTextLabel1.grid(row=row, column=column, padx=5, pady=5)
        _entry[index] = myTextLabel1

_entry[index].configure(bg_color='red') #this changed

root.bind("<Button-1>", on_click)

root.mainloop()

问题原因 #

CustomTkinter的CTkLabel是原生Tkinter标签的包装组件，内部存在名为_label的子组件，点击事件实际触发在这个子组件上，而非CTkLabel本身。原代码中event.widget获取到的是内部子组件，导致isinstance(widget, customtkinter.CTkLabel)判断失败，后续拖拽绑定逻辑无法执行。

修复方案 #

1. 新增工具函数从子组件向上追溯，找到真正的CTkLabel实例
2. 调整拖拽起始坐标计算，抵消内部子组件与CTkLabel的坐标偏移
3. 拖拽释放时，同样处理目标组件为内部子组件的情况

修改后的CustomTkinter代码 #

import customtkinter

def changeOrder(widget1, widget2, initial):
    target = widget1.grid_info()
    widget1.grid(row=initial['row'], column=initial['column'])
    widget2.grid(row=target['row'], column=target['column'])

def get_ctk_label(widget):
    # 从子组件向上查找CTkLabel实例
    while widget:
        if isinstance(widget, customtkinter.CTkLabel):
            return widget
        widget = widget.master
    return None

def on_click(event):
    widget = event.widget
    ctk_label = get_ctk_label(widget)
    print(ctk_label)
    if ctk_label:
        # 计算点击位置相对于CTkLabel的坐标
        start_x = event.x + widget.winfo_x() - ctk_label.winfo_x()
        start_y = event.y + widget.winfo_y() - ctk_label.winfo_y()
        start = (start_x, start_y)
        grid_info = ctk_label.grid_info()
        # 绑定事件到真正的CTkLabel实例
        ctk_label.bind("<B1-Motion>", lambda event: drag_motion(event, ctk_label, start))
        ctk_label.bind("<ButtonRelease-1>", lambda event: drag_release(event, ctk_label, grid_info))
    else:
        root.unbind("<ButtonRelease-1>")

def drag_motion(event, widget, start):
    x = widget.winfo_x() + event.x - start[0]
    y = widget.winfo_y() + event.y - start[1]
    widget.lift()
    widget.place(x=x, y=y)

def drag_release(event, widget, grid_info):
    widget.lower()
    x, y = root.winfo_pointerxy()
    target_widget = root.winfo_containing(x, y)
    target_ctk_label = get_ctk_label(target_widget)
    if target_ctk_label: 
        changeOrder(target_ctk_label, widget, grid_info)
    else:
        widget.grid(row=grid_info['row'], column=grid_info['column'])

root = customtkinter.CTk()
_entry = {}
rows = 3
columns = 2
for row in range(rows):
    for column in range(columns):
        index = (row, column)
        myTextLabel1 = customtkinter.CTkLabel(root, text="Label 1", bg_color='yellow')
        myTextLabel1.grid(row=row, column=column, padx=5, pady=5)
        _entry[index] = myTextLabel1

_entry[index].configure(bg_color='red')

root.bind("<Button-1>", on_click)

root.mainloop()

内容的提问来源于stack exchange，提问作者RafaelTech