Tkinter Variable

trace(self, mode, callback) trace_variable(self, mode, callback) Define a trace callback for the variable. MODE is one of "r", "w", "u" for read, write, undefine. CALLBACK must be a function which is called when the variable is read, written or undefined. Return the name of the callback. 为Tkinter Variable定义一个回调函数,用法如下: >>>import Tkinter >>> def cc(*pa): ... print 'change' ... >>> w=Tkinter.Tk() >>> s=Tkinter.StringVar(w) >>> s.trace_variable('w',cc) '19779416cc' >>> s.set('asfdasdf') change 第一个参数可以是"r", "w"或"u"，分别代表读、写、未定义。第二个参数是一个回调函数。上面的例子是，如果一个窗口变量s被写入，就调用回调函数cc。