GtkAssistant: feature request

[Allin Cottrell <cottrell wfu edu>]

I'm thinking of filing a feature request for GtkAssistant, but I'd 
like to post it here first to see if I'm missing something.

In a non-trivial "wizard"-type process, it's possible that the 
user reaches a dead end: a situation where progress is not 
possible given the data supplied so far -- but where it is OK for 
the user to try going back, or to cancel.

To handle this situation, it would be good to have two things:

(a) the ability to set the "Forward" button insensitive, and

(b) a "forward" signal, emitted when the forward button is 
clicked, to which one could attach a callback with a gboolean 
return: the programmer could check the data for validity and 
return either FALSE to proceed or TRUE to block the forward 
action.

At present we can set the "complete" property on a given assistant 
page TRUE or FALSE, but that's a different thing.  Setting the 
page as not complete disables all the control buttons, but I 
want to be able to disable Forward while leaving Back and Cancel
accessible.

One possibly relevant item in the current API is the 
GtkAssistantPageFunc.  I tried the experiment of connecting a 
function which checks for validity, and if progress is not 
possible, posts an error message and returns the current 
page-number as the "next" page.  Is that supposed to work?  I 
found it confused the Assistant, giving me a blank page. (Via 
debugging statements I can see the "prepare" signal for the page 
in question being processed, yet the page comes up with no 
content).

-- 
Allin Cottrell
Department of Economics
Wake Forest University, NC