Question

这应该很简单，但我真的很难做到正确。我只需要一个简单的ttk ComboBox，它可以根据选择的变化更新变量。

在下面的示例中，我需要每次进行新选择时自动更新value_of_combo变量的值。

from Tkinter import *
import ttk

class App:

    value_of_combo = 'X'


    def __init__(self, parent):
        self.parent = parent
        self.combo()

    def combo(self):
        self.box_value = StringVar()
        self.box = ttk.Combobox(self.parent, textvariable=self.box_value)
        self.box['values'] = ('X', 'Y', 'Z')
        self.box.current(0)
        self.box.grid(column=0, row=0)

if __name__ == '__main__':
    root = Tk()
    app = App(root)
    root.mainloop()

Answer 1

只需将虚拟事件<<ComboboxSelected>>绑定到Combobox小部件：

class App:
    def __init__(self, parent):
        self.parent = parent
        self.value_of_combo = 'X'
        self.combo()

    def newselection(self, event):
        self.value_of_combo = self.box.get()
        print(self.value_of_combo)

    def combo(self):
        self.box_value = StringVar()
        self.box = ttk.Combobox(self.parent, textvariable=self.box_value)
        self.box.bind("<<ComboboxSelected>>", self.newselection)
        # ...

Answer 2

在更一般的情况下，如果您需要在更新变量时获取变量的值，建议使用内置的变量工具。

var = StringVar()  # create a var object

# define the callback
def tracer(name, idontknow, mode):
    # I cannot find the arguments sent to the callback documented
    # anywhere, or how to really use them.  I simply ignore
    # the arguments, and use the invocation of the callback
    # as the only api to tracing
    print var.get()

var.trace('w', tracer)
# 'w' in this case, is the 'mode', one of 'r'
# for reading and 'w' for writing

var.set('Foo')  # manually update the var...

# 'Foo' is printed

简单的ttk ComboBox演示

2 个答案: