Hi James,
On 29 October 2010 05:06, James d'Arcy <james.da...@wraithbane.com> wrote:
> Conceptually what I want to do is create items in the ListCtrl and
> associate a
> unique identifier with each item. This identifier would not be displayed in
> the
> UI. An Int64 would be ideal but a String would be fine. When a user clicks
> on
> the item, I want to be able to retrieve this identifier and use it to find
> the
> associated data, in this case a database record.
>
> The items are inserted into the ListCtrl ok with the following code:
>
> showStudy :: ListCtrl l -> (Int,DicomStudy) -> IO ()
> showStudy wgDbTable (idx,dcmStudy) = do
> listCtrlInsertItemWithData wgDbTable idx $ studyUid dcmStudy
> set wgDbTable [item idx := [(patientName . studyPatient) dcmStudy,
> studyDescription dcmStudy,
> studyDate dcmStudy]]
>
> and the event handler looks like this:
>
> onDbTableEvent :: HasturContext -> EventList -> IO ()
> onDbTableEvent HasturCtx {guiDbTable=wgDbTable, guiSeriesList=wgSeriesList}
> event =
> case event of
> ListItemSelected idx -> do
> studyUid <- listCtrlGetItemData wgSeriesList idx
> infoM "Hastur" $ "DB Table event: " ++ show studyUid
> propagateEvent
> otherwise ->
> propagateEvent
>
> When the user clicks on the ListCtrl item I get an error dialog pop up
> saying:
>
> "Couldn't retrieve information about list control item X"
>
> where X is idx. The infoM call produces:
>
> "DB Table event: 0"
>
> What am I missing? I've tried listCtrl{Get/Set}Data, listCtrl{Get/Set}Text
> all
> with the same result. listCtrlDeleteItem in the event handler doesn't
> delete the
> item but produces the result: False.
>
>
showStudy wgDbTable (idx,dcmStudy) = do
listCtrlInsertItemWithData wgDbTable idx $ studyUid dcmStudy
set wgDbTable [item idx := [(patientName . studyPatient) dcmStudy,
studyDescription dcmStudy,
studyDate dcmStudy]]
I suspect that the problem comes from mixing WXCore and WX functionality
(highlighted in red above if you are using an HTML mailer - otherwise look
at the . I doubt that it is safe to do this.
Below is an example I have tested. I've tried to make it as simple as
possible, so it has a fixed list of (displayed) items, each of which has an
Integer key (which is not displayed - it is stored as a data item). I'll
write it up more fully in my blog (http://wewantarock.wordpress.com)
shortly, but for the moment, just note that I am using the WXCore functions
to insert the item data and the displayed contents.
module Main () where
import Graphics.UI.WXCore
import Graphics.UI.WX
-- Int data and strings for each column
entries
= [ (100, ["BouncingBalls.hs" ,"2402" ,"Jul 19 16:50"])
, (101, ["ByeDemo.hs" ,"1414" ,"Jul 13 23:18"])
, (102, ["Camels.hs" ,"7633" ,"Aug 20 11:57"])
, (103, ["Controls.hs" ,"3862" ,"Aug 20 11:57"])
, (104, ["HelloWorld.hs" ,"1028" ,"Aug 15 10:09"])
, (105, ["ImageViewer.hs" ,"3756" ,"Aug 20 11:57"])
, (106, ["Layout.hs" ,"1075" ,"Jul 13 23:18"])
, (107, ["ListCtrl.hs" ,"750" ,"Sep 8 16:22"])
, (108, ["Minimal.hs" ,"147" ,"Jul 13 23:18"])
, (109, ["Paint.hs" ,"1024" ,"Aug 20 11:57"])
, (110, ["Process.hs" ,"2261" ,"Aug 20 11:57"])
, (111, ["TimeFlows.hs" ,"4929" ,"Aug 20 11:57"])
, (112, ["TimeFlowsEx.hs" ,"8648" ,"Aug 20 11:57"])
, (113, ["desert.bmp" ,"61302" ,"Jul 13 23:31"])
]
main :: IO ()
main
= start gui
gui :: IO ()
gui
= do -- main gui elements: frame, panel, text control, and the notebook
f <- frame [text := "List Sample"]
-- panel: just for the nice grey color
p <- panel f []
textlog <- textCtrl p [enabled := False, wrap := WrapLine]
-- use text control as logger
textCtrlMakeLogActiveTarget textlog
logMessage "logging enabled"
-- list control
l <- listCtrl p [columns := [("Name", AlignLeft, 120)
,("Size", AlignRight, -1)
,("Date", AlignRight, -1)]]
set l [on listEvent := onListEvent l]
mapM_ (setItem l) entries
-- specify layout
set f [layout := container p $ margin 10 $
column 5 [ fill $ widget l
, hfill $ widget textlog
]
,clientSize := sz 400 300
]
return ()
where
onListEvent lc eventList
= case eventList of
ListItemSelected idx -> do
dat <-listCtrlGetItemData lc idx
logMessage ("item selected: " ++ show
idx ++ " Data: " ++ show dat)
ListItemDeselected idx -> logMessage ("item de-selected: " ++
show idx)
other -> logMessage ("list control event.")
setItem lc (key_val, col_txts) =
do
count <- listCtrlGetItemCount lc
idx <- listCtrlInsertItemWithLabel lc count (show count) (-1)
mapM_ (\(column, col_txt) -> listCtrlSetItem lc idx column col_txt
(-1)) (zip [0..] col_txts)
listCtrlSetItemData lc idx key_val
Is what I am trying to achieve possible or would I be better maintaining a
> Data.Map with a mapping between idx and the relevant data? If so, how would
> that
> affect things if the ListCtrl contents are re-ordered (e.g. sort by date)?
>
Hopefully the example shows how to do what you want...
> Sorry if this seems a stupid query, I'm new to Haskell and trying to learn
> after
> years of using imperative languages.
>
It's an entirely sensible question if you ask me, but then I'm also a
recovering imperative programmer :-)
Regards
Jeremy
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