[Tutor] Misunderstanding the Entry Widget

[Alan Gauld]

"Wayne Watson" <sierra_mtnview at sbcglobal.net> wrote 

> Apparently Entry does not have a callback. 

Thats the magic of Control Variables. They automatically 
get populated when the user enters data into the Entry widget.

But since Entry widgets are usually part if a form and there 
will be several of them its more useful to wait for the whole 
form to be complteed and then hit a Submit button. The 
button handler can then read all of the Entry fields using get()

So you are right that there is no callback per se except for 
the auto settigh of control variables, but you can't trigger 
an action based on that. However you can of course bind 
an event to the Entry box such as keypress, mouse over etc.
and the event can trigger an action, so in your example you 
could bind a carriage return keystroke to some action.

See the event handling topic in my tutorial for an example 
of binding a specific key to an event.

-- 
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/