如何在Tkinter Combobox中获取选择选项的索引

Question

下面的代码允许我从组合框中打印出选定的值，但我需要打印（获取）列表中选定项的索引号。你能告诉我怎么做吗？

import Tkinter
import tkMessageBox
from Tkinter import *
import ttk
from ttk import *

app = Tk()

def OptionCallBack(*args):
    print variable.get()

variable = StringVar(app)
variable.set("Select From List")
variable.trace('w', OptionCallBack)

so = ttk.Combobox(app, textvariable=variable)
so.config(values =('Tracing Upstream', 'Tracing Downstream','Find Path'))
so.grid(row=1, column=4, sticky='E', padx=10)


app.mainloop()

Answer 1

在组合框上使用current方法。

import Tkinter
import tkMessageBox
from Tkinter import *
import ttk
from ttk import *

app = Tk()

def OptionCallBack(*args):
    print variable.get()
    print so.current()

variable = StringVar(app)
variable.set("Select From List")
variable.trace('w', OptionCallBack)


so = ttk.Combobox(app, textvariable=variable)
so.config(values =('Tracing Upstream', 'Tracing Downstream','Find Path'))
so.grid(row=1, column=4, sticky='E', padx=10)


app.mainloop()

Answer 2

是的，如果你把^{}和^{}结合在一起，你可以。

下面是一个快速演示：

import Tkinter
import tkMessageBox
from Tkinter import *
import ttk
from ttk import *

app = Tk()

def display_selected_item_index(event): 
   global so
   print 'index of this item is: {}\n'.format(so.current())

def OptionCallBack(*args):
    print variable.get()

variable = StringVar(app)
variable.set("Select From List")
variable.trace('w', OptionCallBack)

so = ttk.Combobox(app, textvariable=variable)
so.config(values =('Tracing Upstream', 'Tracing Downstream','Find Path'))
so.grid(row=1, column=4, sticky='E', padx=10)    
so.bind("<<ComboboxSelected>>", display_selected_item_index)  

app.mainloop()