Flex uses events to cause the UI to update in response to changes in the underlying data.
If you use the correct API to update the data, then Flex will dispatch the necessary events. Common API methods include setItemAt(), addItem(), ... using the API is the best practice. If you manually update a dataProvider item, say by assigning a value to a property, then the necessary events are not dispatched. The collection.itemUpdated() method can be used in this case. See the recent thread "Slow datagrid updates" for example code. Tracy ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Guy Morton Sent: Tuesday, January 06, 2009 7:49 AM To: [email protected] Subject: [flexcoders] DataGrids, itemRenderers and dataChange events Hello I hope someone here will be good enough to help me. I have a DataGrid, and a custom itemRenderer that shows an image depending on the value of the data in that cell. The trouble is that I am updating the value of the data in that cell when I do an update to one of the other cells in that row (via a different itemEditor, triggered by the itemEditEnd event), but that change is not being shown in the cell in question unless it gets redrawn by some other means, eg scrolling the field out of view and back in will show the new data, as will rearranging the columns (presumably because both of these actions force a redraw of the data in the cell in question). Is there a way to force the updated value to trigger a redraw in the cell? My renderer is set up to catch the dataChange event but that doesn't seem to get dispatched unless one of the aforementioned things is done to force it. Am I missing something here? Or is this a flaw in Flex? Guy
