[Tutor] Finding the widget name which generated an event

[Alan Gauld]

>    how can i find the widget name that generated an
> event? 

Technically the widget doesn't have a name.
Instead there is a variable in your code that references 
the widget. You could have several names referring to 
the same widget, in which case which name gets printed?

e = Entry(rt)
e1 = Entry(rt)
e2 = e1

Now does the event on e1 widget print 'e1' or 'e2' since 
both are valid names for the same object!

More pragmatically...

> widget rather than widget name. How can i get the
> widget name that generated an event?
> My coding is given below.
> 
> import Tkinter
> def gotFocus(event):...
> def lostFocus(event):...
> 
> root = Tkinter.Tk()
> 
> e = Tkinter.Entry()
> e1=Tkinter.Entry()

You should really pass a parent to the widgets:

e = Tkinter.Entry(root)

But that doesn't buy you much here.

If you want to have some kind of friendly name printed then
you need to store the widgets in a dictionary or class:

widgets = {}
widgets['e'] = Entry(root)
widgets['e1'] = Entry(root)

Now you can compare the widget id with the objects in 
the dictionary:

for key in widgets.keys():
    if id(e.widget) == id(widgets[key]):
       print "Widget: ", key

Another option involves setting setting separate 
callbacks for each widget:

def gotFocus(event, name): 
    print "Widget: ", name

e.bind('<FocusIn>', lambda ev,nm='e': gotFocus(ev,nm) )
e1.bind('<FocusIn>', lambda ev,nm='e1': gotFocus(ev,nm) )

HTH,

Alan G.
(Back from a very wet vacation!)