我认为正确的方法是对已分配给小部件的 tkinter 变量使用 trace.

I think the correct method is to use trace on a tkinter variable that has been assigned to a widget.

例如...

import tkinter

root = tkinter.Tk()
myvar = tkinter.StringVar()
myvar.set('')
mywidget = tkinter.Entry(root,textvariable=myvar,width=10)
mywidget.pack()

def oddblue(a,b,c):
    if len(myvar.get())%2 == 0:
        mywidget.config(bg='red')
    else:
        mywidget.config(bg='blue')
    mywidget.update_idletasks()

myvar.trace('w',oddblue)

root.mainloop()

跟踪中的 w 告诉 tkinter 每当有人写入(更新)变量时，每次有人在 Entry 小部件中写入内容时都会发生这种情况，请执行 oddblue.跟踪总是将三个值传递给您列出的任何函数，因此您需要在您的函数中期待它们，因此 a,b,c.我通常不使用它们，因为无论如何我需要的一切都是在本地定义的.据我所知，a 是变量对象，b 是空白的(不知道为什么)，c 是跟踪模式(即w).

The w in trace tells tkinter whenever somebody writes (updates) the variable, which would happen every time someone wrote something in the Entry widget, do oddblue. The trace always passes three values to whatever function you've listed, so you'll need to expect them in your function, hence a,b,c. I usually do nothing with them as everything I need is defined locally anyway. From what I can tell a is the variable object, b is blank (not sure why), and c is the trace mode (i.e.w).

有关 tkinter 变量的更多信息，请查看.