Python TKinter OptionMenu：如何获得选定的选项？
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TKinter OptionMenu: How to get the selected choice?
提问by Hymankilby
I am quite new at Python and Tkinter, but I have to create a simple form which requires the use of drop-down menus. I was trying to do something like this:
我是 Python 和 Tkinter 的新手，但我必须创建一个需要使用下拉菜单的简单表单。我试图做这样的事情：
#!/usr/bin python
import sys
from Tkinter import *
# My frame for form
class simpleform_ap(Tk):
def __init__(self,parent):
Tk.__init__(self,parent)
self.parent = parent
self.initialize()
def initialize(self):
self.grid()
# Dropdown Menu
optionList = ["Yes","No"]
self.dropVar=StringVar()
self.dropVar.set("Yes") # default choice
self.dropMenu1 = OptionMenu(self, self.dropVar, *optionList)
self.dropMenu1.grid(column=1,row=4)
print self.dropVar.get()
def create_form(argv):
form = simpleform_ap(None)
form.title('My form')
form.mainloop()
if __name__ == "__main__":
create_form(sys.argv)
However what I get printed out is always the default value and I never get the value that I choose from the drop-down list.
然而，我打印出来的始终是默认值，我从来没有从下拉列表中得到我选择的值。
I tried to use .trace method for the StingVar doing something like this:
我尝试使用 .trace 方法为 StingVar 做这样的事情：
#!/usr/bin python
import sys
from Tkinter import *
# My frame for form
class simpleform_ap(Tk):
def __init__(self,parent):
Tk.__init__(self,parent)
self.parent = parent
self.initialize()
def initialize(self):
self.grid()
# Dropdown Menu
optionList = ["Yes","No"]
self.dropVar=StringVar()
self.dropVar.set("Yes") # default choice
self.dropMenu1 = OptionMenu(self, self.dropVar, *optionList)
self.dropMenu1.grid(column=1,row=4)
self.dropVar.trace("w",self.get_selection)
print self.dropVar.get()
def get_selection(self):
print "Selected: "+ self.dropVar.get()
def create_form(argv):
form = simpleform_ap(None)
form.title('My form')
form.mainloop()
if __name__ == "__main__":
create_form(sys.argv)
But I got the following error:
但我收到以下错误：
Exception in Tkinter callback Traceback (most recent call last):
File "/usr/lib64/python2.6/lib-tk/Tkinter.py", line 1410, in __call__
return self.func(*args) TypeError: get_selection() takes exactly 1 argument (4 given)
What am I doing wrong?
我究竟做错了什么？
Please note, that I would prefer not to use any button to confirm the choice in the drop-down menu.
请注意，我不想使用任何按钮来确认下拉菜单中的选择。
Could you please give some advice?
你能给一些建议吗？
采纳答案by Gábor Erd?s
The OptionMenuhas a built in commandoption, which gives the current state of the menuto a function. See this:
将OptionMenu有一个内置的command选项，这使的当前状态menu的功能。看到这个：
#!/usr/bin python
import sys
from Tkinter import *
# My frame for form
class simpleform_ap(Tk):
def __init__(self,parent):
Tk.__init__(self,parent)
self.parent = parent
self.initialize()
self.grid()
def initialize(self):
# Dropdown Menu
optionList = ["Yes","No"]
self.dropVar=StringVar()
self.dropVar.set("Yes") # default choice
self.dropMenu1 = OptionMenu(self, self.dropVar, *optionList,
command=self.func)
self.dropMenu1.grid(column=1,row=4)
def func(self,value):
print value
def create_form(argv):
form = simpleform_ap(None)
form.title('My form')
form.mainloop()
if __name__ == "__main__":
create_form(sys.argv)
This should do what you wish.
这应该做你想做的。
