关于Python TKinter动态选择菜单的更多信息

Question

我正在尝试修改这里的代码，让用户确认从optionmenus中选择的项目。如果用户点击提交按钮，就应该弹出一个消息框来确认。最后，我想把选中的项目作为变量返回给程序，这样可以在其他函数中进一步处理。不过，我的修改没有成功；它只是返回了一个空窗口。你们觉得我缺少了什么呢？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：现在窗口里有了控件。我之前在按钮前面漏写了self.。不过我还是收到了一个错误信息，我正在尝试解决：AttributeError: 'App'对象没有属性'optionmenu_b'

Answer 1

这里 @sedeh，按照你的想法，这个是可以正常工作的。错误并不是因为你的插件，而是因为你用了 from tkinter import * 这种写法，而不是 import tkinter as tk。所以当你运行代码时，tk窗口一出现就报错了。

我做的就是把你给的链接里的代码拿过来，加上你写的部分，这样就没有错误了。

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()

希望这对你有帮助。