Binding events to widget not working

Question

I have a function, say foo and it's supposed to bind an event

    def foo:
         for x in widget_list:
              widget.config(command = lambda: self.function(widget_list.index(x))

    def function(index):
         do something here....
         print index

The widget list contains buttons, and whenever I click corresponding buttons, they're supposed to print to the IDLE their index, but what happens is that all the buttons I click end up printing the last index of widget_list. I'm guessing that while for iterates, the argument of the function also changes thus only the last index is preserved. Is there anyway to bind the previous indexes to the button?

You guess right that only the last value of x is used in your lambdas. You might find work around in this answer: http://stackoverflow.com/a/2295368 — FabienAndre, Mar 24 '14 at 13:01
Finally. I have been searching for such a solution here for about a week now but I guess I have miscategorized this a a tkinter only problem. Anyways, thank you as I can progress with my work now. :D — user3455382, Mar 24 '14 at 13:14
possible duplicate of [Passing argument to a function via a Button in Tkinter, starnge behaviour in loop](http://stackoverflow.com/questions/18510403/passing-argument-to-a-function-via-a-button-in-tkinter-starnge-behaviour-in-loo) — FabienAndre, Mar 24 '14 at 13:18

score 0 · Accepted Answer · answered Mar 24 '14 at 17:41

The simplest fix is to make sure that your lambda is using the current value of x:

widget.config(command = lambda x=x: self.function(widget_list.index(x))

This forces x to be a default parameter to the function, and the default value will be the value of x at the time the lambda is defined.

Binding events to widget not working

1 Answers1