Refresh a Flex DataGrid

To force a Flex DataGrid to refresh its data (say, after you've updated it), you can call the invalidateDisplayList() method. This causes Flex to in turn execute the component's updateDisplayList() method. This came in handy while writing an image-upload app; after the image is uploaded, I needed the DataGrid's selectedItem to show the image it was associated with; in the overridden set data() method of the itemRenderer, there's code to do a load() of the image from the server.

The Power of Flex's resultFormat E4X

While researching how to bind XML data to a Flex AdvancedDataGrid, I saw various examples that had the data converted to array objects. That might have been the only way to work with XML prior to ActionScript 3.0. Now however, a new set of classes and functionality, known as E4X (ECMAScript-for-XML), make life easier for developers.

Playing around, I discovered that, on the HTTPService object, a simple property allows the data to be accessible via simple XML calls,

service.resultFormat = "e4x";

This enables your datagrid's columns' dataField to simply have your XML element or attribute name as its value. For example, to read an id attribute off of the root element of your XML, you'd use dataField="@id".