一种方法是利用可变类（的
BooleanVar，
DoubleVar，
IntVar，
StringVar，
Variable），以及它们的
trace_add方法。当实例拥有的值被修改时，它允许调用一个方法。
try: # In order to be able to import tkinter for import tkinter as tk # either in python 2 or in python 3except importError: import Tkinter as tkdef do_stuff(*_): # trace_add implicitly passes 3 internal arguments demo['text'] = var.get() # to obtain the value var holdsif __name__ == '__main__': root = tk.Tk() var = tk.StringVar(value="Value") #var = tk.BooleanVar(value=True) #var = tk.DoubleVar(value=2.78) #var = tk.IntVar(value=0) #var = tk.Variable(value=["Value", True, 2.78, 0]) demo = tk.Label(root, text=var.get()) demo.pack() var.trace_add('write', do_stuff) # call do_stuff when var is set var.set("New Value") # to replace the value var holds #var.set(False) #var.set(3.14) #var.set(42) #var.set(["New Value", False, 3.14, 42]) tk.mainloop()还需要注意的是，尽管并非总是实用，但某些小部件具有变量选项（变量，文本变量，列表变量），这些选项允许它们持有的值与变量类对象的值同步。下面的示例利用了这一点：
try: # In order to be able to import tkinter for import tkinter as tk # either in python 2 or in python 3except importError: import Tkinter as tkif __name__ == '__main__': root = tk.Tk() var = tk.StringVar(value="Value") demo = tk.Label(root, textvariable=var) demo.pack() var.set("New Value") # label is in sync right-away tk.mainloop()另一种方法是在使用class时
__setattr__利用对象的属性分配魔术方法。
例如，
demo标签将在每次
self.string修改属性时更新：
try: # In order to be able to import tkinter for import tkinter as tk # either in python 2 or in python 3except importError: import Tkinter as tkclass MyLabel(tk.Label): def __init__(self, master, var="", *args, **kwargs): tk.Label.__init__(self, master, *args, **kwargs) self.var = var def __setattr__(self, name, value): self.__dict__[name] = value if name == 'var': self.do_stuff() def do_stuff(self): self['text'] = self.varif __name__ == '__main__': root = tk.Tk() demo = MyLabel(root, "Value") demo.pack() demo.var = "New Value" tk.mainloop()
