python - 有关 Python TKinter 动态选项菜单的更多信息

Question

我正在尝试修改 code here让用户确认从选项菜单中选择的项目。如果用户单击“提交”按钮，则会打开一个消息框提示确认。最后，我希望所选项目作为变量返回到程序，以便它们可以在其他函数中使用以进行进一步处理。然而我的修改并没有起作用；它只是返回一个空窗口。想想我缺少什么？非常感谢。

from tkinter import *
import tkinter.messagebox

class App(Frame):
    def __init__(self, master):
        Frame.__init__(self, master)
        self.dict = {'Asia': ['Japan', 'China', 'Malasia'],
                     'Europe': ['Germany', 'France', 'Switzerland'],
                     'Africa': ['Nigeria', 'Kenya', 'Ethiopia']}
        self.variable_a = StringVar(self)
        self.variable_b = StringVar(self)
        self.variable_a.trace('w', self.updateoptions)
        self.optionmenu_a = OptionMenu(self, self.variable_a, *self.dict.keys())
        self.variable_a.set('Asia')
        self.optionmenu_a.pack()
        self.optionmenu_b = OptionMenu(self, self.variable_b, ())
        self.optionmenu_b.pack()
        self.btn = Button(self, text="Submit", width=8, command=self.submit)
        self.btn.pack()
        self.pack()

    def updateoptions(self, *args):
        countries = self.dict[self.variable_a.get()]
        self.variable_b.set(countries[0])
        menu = self.optionmenu_b['menu']
        menu.delete(0, 'end')
        for country in countries:
            menu.add_command(label=country, command=lambda country=country: self.variable_b.set(country))
    
    def submit(self, *args):
        var1 = self.variable_a.get()
        var2 = self.variable_b.get()
        if tkinter.messagebox.askokcancel("Selection", "Confirm selection: " + var1 + ' ' + var2):
            print(var1, var2) #Or can be other function for further processing
         

root = Tk()
app = App(root)
app.mainloop()

Python 版本 3.4.1

编辑:窗口现在与小部件一起出现。我在按钮前面省略了 self. 。我仍然收到一条错误消息，我正在尝试解决该错误消息: AttributeError: 'App' object has no attribute 'optionmenu_b'

Answer 1

在这里@sedeh，这可以按照您的意愿工作。该错误不是来自您的附加组件，但我认为是使用 from tkinter import * 而不是 import tkinter as tk 造成的，这就是运行代码时出现错误的原因一旦 TK 窗口出现。

我所做的是从您提供的链接中获取代码，添加您所做的内容，并且它的工作没有错误。

import tkinter as tk
import tkinter.messagebox

class App(tk.Frame):
    def __init__(self, master):
        tk.Frame.__init__(self, master)
        self.dict = {'Asia': ['Japan', 'China', 'Malasia'],
                     'Europe': ['Germany', 'France', 'Switzerland'],
                     'Africa': ['Nigeria', 'Kenya', 'Ethiopia']}
        self.variable_a = tk.StringVar(self)
        self.variable_b = tk.StringVar(self)
        self.variable_a.trace('w', self.updateoptions)
        self.optionmenu_a = tk.OptionMenu(self, self.variable_a, *self.dict.keys())
        self.optionmenu_b = tk.OptionMenu(self, self.variable_b, '')
        self.variable_a.set('Asia')
        self.optionmenu_a.pack()
        self.optionmenu_b.pack()
        self.btn = tk.Button(self, text="Submit", width=8, command=self.submit)
        self.btn.pack()
        self.pack()
    def updateoptions(self, *args):
        countries = self.dict[self.variable_a.get()]
        self.variable_b.set(countries[0])
        menu = self.optionmenu_b['menu']
        menu.delete(0, 'end')
        for country in countries:
            menu.add_command(label=country, command=lambda country=country: self.variable_b.set(country))

    def submit(self, *args):
        var1 = self.variable_a.get()
        var2 = self.variable_b.get()
        if tkinter.messagebox.askokcancel("Selection", "Confirm selection: " + var1 + ' ' + var2):
            print(var1, var2) #Or can be other function for further processing

root = tk.Tk()
app = App(root)
app.mainloop()

希望这对您有帮助。