| Re: IDL listbox [message #23819 is a reply to message #23735] |
Fri, 16 February 2001 15:18   |
Stuart Norton
Messages: 3
Registered: February 2001
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Junior Member |
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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
>
>
------------------------------------------------------------ ----------
--- Stuart Norton ---
--- stuart@ucolick.org ---
--- Astronomy & Astrophysics - University of California ---
--- Santa Cruz, CA 95064 ---
--- (831) 459-4362 ---
------------------------------------------------------------ ----------
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