Hi Maurice, Thanks for digging into this. ValidateNow() can fix a lot of things, but it can also cause inefficiencies if the things it validates were going to get invalidated shortly after. I don't know if that is the case or not here.
If it were me (and it isn't) I would change the collectionChangeHandler to set a flag and call updateCaretForDataProviderChange in updateDisplayList. InvalidateDisplayList is called in the collectionChangeHandler, and in theory, stuff like contentHeight should be resolved by the time you get to updateDisplayList. Last night I checked in a fix for another similar DG issue in a similar way by deferring work to measure(). -Alex On 10/11/13 6:55 AM, "Maurice Amsellem" <maurice.amsel...@systar.com> wrote: >Hi, I would like your help on a fix for > >https://issues.apache.org/jira/browse/FLEX-33813 (DataGrid goes blank >when scrolled and content is reset) > >I managed to spot where the issue is: > >Grid.as >line 850: >const gridViewLayout:GridViewLayout = centerGridView.gridViewLayout; > const gridMaxVSP:Number = contentHeight - height; >const centerContentHeight:Number = >Math.ceil(gridViewLayout.gridDimensionsView.getContentHeight()); > const centerMaxVSP:Number = centerContentHeight - centerGridView.height; >const vsp:Number = (centerMaxVSP / gridMaxVSP) * value; > centerGridView.verticalScrollPosition = vsp; > >=> contentHeight is NaN so all computations fails and >verticalScrollPosiiton is set to NaN, which clears all the renderers >(goes blank) > >My assumption is that the Grid is not ready yet, so it's missing a >validateNow() somewhere(). > >Call chain: >Grid.dataProvider_collectionChangeHandler(event:CollectionEvent) >=> Grid.updateCaretForDataProviderChange(event:CollectionEvent):void > >In Grid.updateCaretForDataProviderChange(): [line 5356], >when managing RESET event in line 5448, >if the caret is not found (which is the case, since all data is new), we >call directly >verticalScrollPosition = 0; > >=> I added validateNow() before the call, and it's fixed. > >Do you validate ? > >Maurice > > >Maurice Amsellem >SYSTAR R&D - BusinessBridgeFX >
