如何从顶级组合框中获取用户选择的选项

Question

I'm new to Python and Tkinter and was trying to create an interface to search & plot data. I created a very simple toplevel window to get the values from a combobox that would be selected from users. However, I find the script would only print the first item in the list if comboxlist2.current(0) was set or it would print nothing, no matter which one is selected in the box. I created a sample script to test this. If I click on the "search & create", then the return values can change according to the user selection in comboxlist1 , while it would all return "1" no matter what the user selected in comboxlist2 . So may I ask where is the issue and how to solve?

Thanks in advance for the potential suggestions or solutions!

import tkinter as tk
from tkinter import ttk
from tkinter import *

def root_print():    
    reg_in = comboxlist1.get()
    print(reg_in)   #print the value selected

def on_click():
    tl = Toplevel()
    comvalue2 = tk.StringVar()
    comboxlist2 = ttk.Combobox(tl,textvariable=comvalue2)
    comboxlist2["values"] = ("1","2","3")
    comboxlist2.grid()
    comboxlist2.current(0)  #select the first one as default
    #mm = comboxlist2.get()
    #print(mm)              #print directly
    go(comboxlist2,tl)
    tl.wait_window()
    return

def go(comboxlist2,tl):
    mm = comboxlist2.get()
    Button(tl,text='go', command=lambda:test(mm)).grid()

def test(mm):
    print(mm)       #do the same thing for the comboxlist2

root = Tk()
root.title('search')      #create an interface
root.geometry('+400+200')       #size and position

Label(text='region    ').grid(row=2,column=0)
comvalue1 = tk.StringVar()
comboxlist1=ttk.Combobox(root,textvariable=comvalue1) 
comboxlist1["values"]=("all","africa","asia","australia","canada","europe","mexico","southamerica","usa")
comboxlist1.grid(row=2,column=1)
comboxlist1.current(0)
Button(text='search & create', command=root_print).grid(row=0,column=4)
Button(text='click', command=on_click).grid(row=1, column=4)
loop = mainloop()#go!

Answer 1

Here is the working code, which should take care of your needs. I have removed the imports and some code snippets which are not useful.

import tkinter as tk
from tkinter import ttk

def root_print():
    reg_in = comboxlist1.get()
    print(reg_in)

def on_click():
    tl = tk.Toplevel()
    comvalue2 = tk.StringVar()
    comboxlist2 = ttk.Combobox(tl,textvariable=comvalue2)
    comboxlist2["values"] = ("1","2","3")
    comboxlist2.grid()
    comboxlist2.current(0)  #select the first one as default
    tk.Button(tl,text='go', command=lambda: test(comboxlist2.get())).grid()
    tl.wait_window()

def test(mm):
    print(mm)

root = tk.Tk()
root.title('search')      #create an interface
root.geometry('+400+200')       #size and position

tk.Label(text='region    ').grid(row=2,column=0)
comvalue1 = tk.StringVar()
comboxlist1=ttk.Combobox(root,textvariable=comvalue1) 
comboxlist1["values"]=("all","africa","asia","australia","canada","europe","mexico","southamerica","usa")
comboxlist1.grid(row=2,column=1)
comboxlist1.current(0)
tk.Button(text='search & create', command=root_print).grid(row=0,column=4)
tk.Button(text='click', command=on_click).grid(row=1, column=4)
root.mainloop()