wxperl-users

[wxperl-users] Pattern for update forms

[Johan V. <jvr...@sq...>]

Hi,

Given a form with data (in text widgets, checkboxes, and so on). This
data comes from a database. On the form, the user can make changes. On
the bottom there are the familiar buttons Cancel, OK and Reset.

I need to keep track of changes. In particular, I need to know if
anything changed from the start. If so, I can enable the OK and Reset
buttons. If nothing has changed, these are disabled (again).

My usual approach is to make a copy of all data when the form is first
filled, and use the idle loop to compare all fields to see if
something has changed. This works, but I assume there are better ways.

What would be a good pattern for this? Listen to focus in / focus out
events? How do you do this?

-- Johan

Re: [wxperl-users] Pattern for update forms

[Jouke V. <jo...@pv...>]

Hi Johan,

> I need to keep track of changes. In particular, I need to know if
> anything changed from the start. If so, I can enable the OK and Reset
> buttons. If nothing has changed, these are disabled (again).
> 
> My usual approach is to make a copy of all data when the form is first
> filled, and use the idle loop to compare all fields to see if
> something has changed. This works, but I assume there are better ways.
> 
> What would be a good pattern for this? Listen to focus in / focus out
> events? How do you do this?
Yes. For this I usually use the EVT_KILL_FOCUS. If you want to be able 
to track the changes even when the field still has the focus, you can 
use EVT_TEXT on the textcontrol for example.

HTH,

Jouke

Re: [wxperl-users] Pattern for update forms

[<jvr...@sq...>]

[Quoting Jouke Visser, on June 28 2006, 21:38, in "Re: [wxperl-users] P"]
> Yes. For this I usually use the EVT_KILL_FOCUS.

The problem with this approach is that this event is also generated
when the window loses focus for any other reason, e.g., when a system
pop-up temporarily grabs then focus. This causes the "this field has
changed" logic to trigger before the field entry is complete.

For example, if a field must contain a 4 digit code, and a system
pop-up appears when the user has entered only 3 digits, after
dismissal of the pop-up he will get a warning that the input is
only 3 digits, and hence invalid.

-- Johan