Re: IDL listbox

[Stuart Norton <stuart(at)isis.ucolick.org>]

Thanks to all who replied.  widget_info was the key I needed!

(BTW, I am already the proud owner of one copy - wait, no, two copies - of
IDL Programming Techniques!  Is it possible the answer wasn't in there?...
Nah, I must have missed it.  ;-)

Stuart


On Fri, 16 Feb 2001, JD Smith wrote:

> Stuart Norton wrote:
> > 
> > Sorry if this is an obvious one, but I've been trying for too long now...
> > 
> > How do you get a list of all selected items from a widget_listbox?  I have
> > a listbox which I want to handle multiple selections.  I was originally
> > going to use the event handler: just toggle the settings of each item
> > which was clicked... but (at least in Unix) when you single click without
> > holding shift or control, all previous selections in a listbox are
> > de-selected.  I don't know how to keep track of which items are
> > de-selected like this.  (There doesn't seem to be an event for that.)
> > 
> > Another possibility was the OnSelectValue parameter to widget_listbox; I
> > created a procedure to remember if any given item was selected, but
> > again I have the problem that de-selection is not handled.
> > 
> > There ought to be an easy way, say from widget_control, to return an array
> > of indices which are selected at the moment, or something like that.  Why
> > can't I find such a thing??
> 
> 
> This is starting to be the #2 all-time FAQ, after color decomposition,
> of course.  For whatever inane reasons (most likely because the
> functionality was added only a few releases ago), getting the indices of
> multiply selected list widgets requires a visit to our friend
> widget_info:
> 
> list=widget_info(self.list,/LIST_SELECT)
> 
> Now, why this functionality is here instead of 
> 
> widget_control,self.list,get_value=list
> 
> it's best not to ask.  If you want the items on the list themselves,
> you'll have to store them somewhere for access.
> 
> JD
> 
> 

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---                         Stuart Norton                          ---
---                       stuart@ucolick.org                       ---
---	Astronomy & Astrophysics  -  University of California      ---  
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