Tkinter框架切换异常：多框架同时显示无法切换的修复

问题现象 #

所有框架同时显示且无法隐藏，框架切换功能完全失效。

关键缺陷 #

• main_menuHauptmenu类中的Combobox未绑定选择事件，仅定义lambda表达式但未触发执行，导致选择选项后无法切换框架；
• lange类创建gl_frame时未指定父容器，使得该框架直接显示在主窗口而非当前lange实例内部，造成多框架叠加显示；
• main类中重复初始化self.frames变量，属于冗余代码。

修复措施 #

1. 为unit_modus Combobox绑定<<ComboboxSelected>>事件，触发框架切换逻辑；
2. 修改lange类中gl_frame的创建代码，指定父容器为当前lange实例；
3. 删除main类中重复的self.frames = {}语句。

修复后的完整代码 #

import tkinter as tk
from tkinter import ttk

class main(tk.Tk):
    def __init__(self, *args, **kwargs):
        tk.Tk.__init__(self, *args, **kwargs)
        self.resizable(height=1000, width=700)
        self.title("a")
        root = tk.Frame(self)
        root.pack(fill="both", expand=True)
        self.frames = {}
        container = tk.Frame(self)
        container.pack(side="top", fill="both", expand=True)
        container.grid_rowconfigure(0, weight=1)
        container.grid_columnconfigure(0, weight=1)
        # 移除重复的self.frames初始化
        for F in (main_menuHauptmenu, lange):
            frame = F(container, self)
            self.frames[F] = frame
            frame.grid(row=0, column=0, sticky="nsew")
        self.show_frame(main_menuHauptmenu)
    def show_frame(self, page_name):
        frame = self.frames[page_name]
        frame.tkraise()

class main_menuHauptmenu(ttk.Frame):
    def __init__(self, parent, controller):
        tk.Frame.__init__(self, parent)
        hm_label = ttk.Label(self, text="Select Conversion Mode", font=("Times New Roman", 20))
        hm_label.grid(row=0, column=0)
        unit_modus = ttk.Combobox(self)
        unit_modus['values'] = ('Länge',)  # 修正为元组，避免单个元素被解析为字符串
        unit_modus['state'] = 'readonly'
        unit_modus.grid(row=0, column=1)
        # 绑定Combobox选择事件
        unit_modus.bind("<<ComboboxSelected>>", lambda e: controller.show_frame(lange))

class lange(tk.Frame):
    def __init__(self, parent, controller):
        tk.Frame.__init__(self, parent)
        # 指定父容器为当前lange实例
        gl_frame = tk.Frame(self)
        gl_frame.pack()
        of = tk.Frame(gl_frame)
        of.pack(side='left')
        pf = tk.Frame(gl_frame)
        pf.pack(side='left')
        rf = tk.Frame(gl_frame)
        rf.pack(side='right')
        qf = tk.Frame(gl_frame)
        qf.pack(side='right')
        ##  Label
        Masseneinheit1 = tk.Label(of, text="Masseneinheit 1:").pack(side='top', anchor='nw')
        Masseneinheit2 = tk.Label(of, text="Masseneinheit 2:").pack(side='top', anchor='nw')
        ## Entry
        def validate_entry(text):
            if (
                all(char in "0123456789.-" for char in text) and
                "-" not in text[1:] and
                text.count(".") <= 1):
                       return True
            else:
                return False
        nz = tk.StringVar()
        ez = tk.Entry(pf, textvariable=nz, validate='key')
        ez['validatecommand'] = (ez.register(validate_entry), '%P')
        ez.pack(side='top')
        resl = tk.StringVar()
        res = tk.Label(pf, textvariable=resl)
        res.pack(side='top')
        ## Combobox 
        enm = tk.StringVar()
        em = ttk.Combobox(qf, textvariable=enm)
        em['values'] = ('km', 'hm', 'dam', 'm', 'dm', 'cm', 'mm', 'in', 'ft', 'yd', 'mi')
        em['state'] = 'readonly'
        em.pack(side='top', anchor='ne')
        em.current()
        znm = tk.StringVar()
        zm = ttk.Combobox(qf, textvariable=znm)
        zm['values'] = ('mm', 'cm', 'dm', 'm', 'dam', 'hm', 'km', 'mi', 'yd', 'ft', 'in')
        zm['state'] = 'readonly'
        zm.pack(side='top', anchor='ne')
        zm.current()
        # 单位转换系数
        km = 1000
        hm = 100
        dam = 10
        m = 1
        dm = 0.1
        cm = 0.01
        mm = 0.001
        inch = 0.0254
        ft = 0.3048
        yd = 0.9144
        mi = 1609.34
        def conv():   
            # 获取转换系数
            er = km if em.get() == "km" else hm if em.get() == "hm" else m if em.get()\
                == "m" else dam if em.get() == "dam" else \
                dm if em.get() == "dm" else cm if em.get() == "cm" else \
                    mm if em.get() == "mm" else inch if em.get() == "in" else \
                        ft if em.get() == "ft" else yd if em.get() == "yd" else \
                            mi               
            zw = km if zm.get() == "km" else hm if zm.get() == "hm" else \
                m if zm.get() == "m" else dam if zm.get() == "dam" else \
                dm if zm.get() == "dm" else cm if zm.get() == "cm" else \
                    mm if zm.get() == "mm" else inch if zm.get() == "in" else \
                        ft if zm.get() == "ft" else yd if zm.get() == "yd" else \
                            mi
            # 检查输入是否为空，避免转换报错
            if nz.get():
                a = float(nz.get()) * er / zw
                resl.set(format(a, '.16f').rstrip('0').rstrip('.'))
        button = tk.Button(rf, text="Umrechnen!", command=conv)
        button.pack(side='top', anchor='ne')

app = main()
app.mainloop()

额外优化说明：

• 修正unit_modus['values']为元组格式，避免单个元素被解析为字符串导致Combobox显示异常；
• 在转换函数中增加输入为空判断，防止空值转换报错；
• 移除冗余的变量定义，简化代码结构。

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