如何根据另一个组合框的选择来填充一个组合框？

Question

我正在尝试根据另一个组合框的选择来填充组合框。如果我使用更新按钮来更新组合框#1 选择，我就可以做到这一点。但是，我想动态进行更新。

我附上了一个简单的代码示例，除了一个问题之外，该代码似乎按预期工作。您必须选择组合框 #1 两次才能更新组合框 #2。如果有人对两个如何解决这个问题有任何想法，我们将不胜感激。因为我是通过示例学习的，所以请您提供一个代码示例。

预先感谢您：begez

from tkinter import *
import tkinter.ttk,csv

global CategoryCombo

def getUpdateData():

    cat = CategoryCombo.get()
    if cat == 'car':
        AccountCombo = tkinter.ttk.Combobox( width = 15,value = car)
        AccountCombo.grid(row = 5,column = 1,pady = 25,sticky = E)
    elif cat == 'home':
        AccountCombo = tkinter.ttk.Combobox( width = 15,value = home)
        AccountCombo.grid(row = 5,column = 1,pady = 25,sticky = E)
    elif cat == 'rv':
        AccountCombo = tkinter.ttk.Combobox( width = 15,value = rv)
        AccountCombo.grid(row = 5,column = 1,pady = 25,sticky = E)


category = ['home','car','rv']

home = ['utilities','rent','cable']

car = ['gas','oil','repairs']

rv = ['parks','maintenance','payment']
v = StringVar

root = tkinter.Tk()

class Application(Frame):

    def __init__(self, master=None, Frame=None):
        Frame.__init__(self, master)
        super(Application,self).__init__()
        self.grid(column = 5,row = 20,padx = 50,pady = 50)
        self.createWidgets()


    def createWidgets(self):
        global CategoryCombo

        CatCBLabel = Label(text = 'Combo Box #1:').grid(row = 2,column = 1,padx = 10)
        ActCBLabel = Label(text = 'Combo Box #2:').grid(row = 4,column = 1,padx = 10)
        AccountCombo = tkinter.ttk.Combobox( width = 15)
        AccountCombo.grid(row = 5,column = 1,pady = 25,padx = 10)
        CategoryCombo = tkinter.ttk.Combobox(width = 15,values = category,textvariable = v,postcommand = getUpdateData)
        CategoryCombo.grid(row = 3,column = 1,padx = 10,pady = 25)
        print(v)



app = Application()

app.master.title('Yearly Budget Setup')

app.mainloop()

Answer 1

1. 不要使用全局变量。请改用类变量。
2. 使用字典而不是多个变量。
3. 使用 ComboboxSelected 事件

结果：

from tkinter import *
import tkinter.ttk

category = {'home': ['utilities','rent','cable'],
    'car': ['gas','oil','repairs'],
    'rv':['parks','maintenance','payment']}

class Application(Frame):

    def __init__(self, master=None, Frame=None):
        Frame.__init__(self, master)
        super(Application,self).__init__()
        self.grid(column = 5,row = 20,padx = 50,pady = 50)
        self.createWidgets()

    def getUpdateData(self,  event):
        self.AccountCombo['values'] = category[self.CategoryCombo.get()]

    def createWidgets(self):
        Label(text = 'Combo Box #1:').grid(row = 2,column = 1,padx = 10)
        Label(text = 'Combo Box #2:').grid(row = 4,column = 1,padx = 10)
        self.AccountCombo = tkinter.ttk.Combobox( width = 15)
        self.AccountCombo.grid(row = 5,column = 1,pady = 25,padx = 10)

        self.CategoryCombo = tkinter.ttk.Combobox(width = 15,  values = list(category.keys()))
        self.CategoryCombo.bind('<<ComboboxSelected>>', self.getUpdateData)
        self.CategoryCombo.grid(row = 3,column = 1,padx = 10,pady = 25)

app = Application()
app.master.title('Yearly Budget Setup')
app.mainloop()