Comments on: Another Flex Weirdness/Gotcha

By: wellings.eu » Updating a datagrid dataprovider with custom item renderer not working as expected?

Tue, 07 Dec 2010 20:10:16 +0000

[...] http://www.barneyb.com/barneyblog/2007/06/23/another-flex-weirdnessgotcha/ About Visit 's Website. View other posts by [...]

By: David Lincoln

David Lincoln — Mon, 04 Oct 2010 12:33:48 +0000

I have a similar weirdness. The ArrayCollection. refresh() works as expected. But it has a side effect. If the number of rows in my datagrid exceeds the capability of the window it is in, (vertical scroll bars are needed), then when I click in a row after the first couple, the screen refreshes automatically and scrolls up past the row I clicked on. I have tried capturing the verticalSrollPosition of the datagrid prior to the refresh, then resetting it afterward, but that does not help. It's like a catch-22. Either the cell does not refresh properly and the scroll works fine, or vice-versa.

By: BS_C3

BS_C3 — Sun, 21 Mar 2010 12:28:06 +0000

Hi!

That's a really interesting post (it actually helped me solve a problem that was driving me crazy!!).

I had the same issue with a linkbar. The dataprovider was an array collection that looked like

.
.
.

The labels where not updated when the variables value changed… I had to force a dataprovider.refresh() to get it work. It took me some time and some posts to figure it out.

The most interesting thing is that this "weirdness" still exists in flex 3.2 …

And just FYI, a quite useful link about dataproviders limitations:
http://www.adobe.com/devnet/flex/quickstart/using_data_providers/#limitations

Regards,
BS_C3

By: Jon

Jon — Sun, 17 Jan 2010 01:45:27 +0000

Gotta say thanks for this….was driving me crazy.

ArrayCollection(dataGrid.dataProvider).refresh(); worked perfectly for me.

By: Dylan

Dylan — Wed, 30 Sep 2009 01:16:40 +0000

I was having a similar problem using a repeater with a custom component that has a nested second repeater. Repeater A was registering updates to the Bindable object just fine but Repeater B was not updating itself even though the ArrayCollection B it was using as a dataSource had changed.

I tried invalidating the components housing the repeaters but that did not work. I finally took a stab at useing the arrayCollection.refresh() and it worked like magic. Note: everything is [Bindable], it just another one of those quirks.

By: Vitaly Sazanovich

Vitaly Sazanovich — Thu, 20 Aug 2009 23:05:11 +0000

I also had a similar problem. My DataGrid would update its content only when the popup was opened for the first time. I debugged this into a stale reference to the old instance of the DataGrid. I'm using PureMVC and in the constructor of the mediator for the Popup I was registering mediators for canvases within that popup:
facade.registerMediator(new AdPlacesCanvasMediator(settingsTitleWindow.adPlacesCanvas));
Now, the fix was to unregister them in the onClose event:
facade.removeMediator(AdPlacesCanvasMediator.NAME);
Otherwise a new set of mediators would be created with the next popup. Is it a bug of PureMVC? RegisterMediator should take mediator's name as a parameter and do not create a new instance of the mediator if it is already registered.

By: Terry

Terry — Wed, 05 Aug 2009 19:12:09 +0000

I had a similar problem. In the snippet below dataObjects is an ArrayCollection that was set as my dataProvider on my AdvancedDataGrid. I could not get updates to refresh until I added the last line.

public function changeData(event:MouseEvent):void {
var data:Array = dataObjects.getItemAt(2) as Array;
data[1] = "pmWizard";

data = dataObjects.getItemAt(1) as Array;
data[1] = "treeKing";
data[4] = 1967;

ArrayCollection(dataGrid.dataProvider).refresh();
}

By: Garnet

Garnet — Thu, 31 Jul 2008 23:49:24 +0000

I agree about weirdness. It's easy to do cool stuff in Flex quickly, but then you run into a quirk that takes way too long to solve.

I have this as the data provider for my AdvancedDataGrid:
private var dpList:ArrayCollection = new ArrayCollection([
{Ref:true, Name:"Garnet",
ReadTime:400}]);

In timer routines I want to
dpList[0].ReadTime++

But the grid won't update. I tried all of these, and none of them work to cause an update:
dpList.refresh();
adgList.validateNow();
adgList.executeBindings(false);

The one thing that does work is doing
dpList.addItem(…)

Guess I need to trace into the source for addItem and figure out what it is doing.

By: William Henry

William Henry — Thu, 03 Apr 2008 23:01:26 +0000

You can use myDataGrid.executeBindings(false);
The argument determines whether there is recursion.

By: barneyb

barneyb — Sun, 24 Jun 2007 16:07:00 +0000

Thanks for the comments. I'm aware of how to make it work, I'm just surprised it doesn't work by default. I.e. there aren't per-property watchers, just per-object watchers. Refreshing the provider, reexecuting bindings, putting ChangeWatchers on the properties manually, etc., would al work, but it just seems weird to have to do that manually. I haven't tried it, but I'd be willing to bet that a custom itemRenderer that manually binds itself to the specific property (but is otherwise a "normal" renderer) would fix the issue. Then you could just use that in all your DataGrids and have it taken care of "automatically".