如何通过下拉框禁用/启用小部件？

Question

有没有办法通过下拉框（比如选项菜单）来切换一个小部件的启用和禁用状态？

我的意思是，当选择某个选项时就启用它，选择其他选项时就禁用它……

如果可以的话，怎么做呢？

我试过类似的代码，但没有成功……

op = StringVar(root)
op.set("------")
o0 = OptionMenu(root, op, "opt1", "opt2", "opt3","opt4")

if op.get() is "opt1":
    e_state = 'ENABLED'
else:
    e_state = 'DISABLED'

en9 = Entry(root, width = 30, background = 'white', textvariable = seccion, state=e_state)

Answer 1

是的，这是可能的。下面是一个例子：

import Tkinter as tk

class App(tk.Tk):
    def __init__(self, *args, **kwargs):
        tk.Tk.__init__(self, *args, **kwargs)
        self.op = tk.StringVar(self)
        self.op.set("enable")
        self.om = tk.OptionMenu(self, self.op, "enable","disable", command=self.OnOption)
        self.entry = tk.Entry(self, width=30)
        self.om.pack()
        self.entry.pack()

    def OnOption(self, event):
        state = "normal" if self.op.get() == "enable" else "disabled"
        self.entry.configure(state=state)

app=App()
app.mainloop()