Question

我想知道当用户从下拉列表中选择一个项目时是否有办法从ttk.Combobox调用回调。我想检查单击项目时组合框的值是什么，这样我就可以在给定组合框键的情况下显示相关的字典值。

import Tkinter
import ttk

FriendMap = {}
UI = Tkinter.Tk()
UI.geometry("%dx%d+%d+%d" % (330, 80, 500, 450))
UI.title("User Friend List Lookup")

def TextBoxUpdate():
    if not  FriendListComboBox.get() == "":
        FriendList = FriendMap[FriendListComboBox.get()]
        FriendListBox.insert(0,FriendMap[FriendListComboBox.get()])`

#Imports the data from the FriendList.txt file
with open("C:\Users\me\Documents\PythonTest\FriendList.txt", "r+") as file:
for line in file:
    items = line.rstrip().lower().split(":")
    FriendMap[items[0]] = items[1]

#Creates a dropdown box with all of the keys in the FriendList file
FriendListKeys = FriendMap.keys()
FriendListKeys.sort()
FriendListComboBox = ttk.Combobox(UI,values=FriendListKeys,command=TextBoxUpdate)`

最后一行显然不起作用，因为Comboboxes没有'命令'，但我不确定我需要做什么才能让它工作。任何帮助将不胜感激。

Answer 1

您可以绑定<<ComboboxSelected>>事件，只要组合框的值发生变化，该事件就会触发。

def TextBoxUpdate(event):
    ...
FriendListComboBox.bind("<<ComboboxSelected>>", TextBoxUpdate)

Answer 2

使用IntVar和StringVar。

您可以使用trace方法将“observer”回调附加到变量。只要内容发生变化，就会调用回调：

import Tkinter
import ttk

FriendMap = {}
UI = Tkinter.Tk()
UI.geometry("%dx%d+%d+%d" % (330, 80, 500, 450))
UI.title("User Friend List Lookup")

def TextBoxUpdate():
    if not  FriendListComboBox.get() == "":
        FriendList = FriendMap[FriendListComboBox.get()]
        FriendListBox.insert(0,FriendMap[UserListComboBox.get()])`
def calback():
    print("do something")

#Imports the data from the FriendList.txt file
with open("C:\Users\me\Documents\PythonTest\FriendList.txt", "r+") as file:
for line in file:
    items = line.rstrip().lower().split(":")
    FriendMap[items[0]] = items[1]

#Creates a dropdown box with all of the keys in the FriendList file
value = StringVar()
value.trace('w', calback)
FriendListKeys = FriendMap.keys()
FriendListKeys.sort()
FriendListComboBox =   ttk.Combobox(UI,values=FriendListKeys,command=TextBoxUpdate,textvariable=value)`

当comobox更改

时将调用回调函数

如何制作ttk.Combobox回调

2 个答案: