RE: [flexcoders] Defining item renderers for a DataGrid using ActionScript

[Alex Harui]

By default, checkbox assumes the data[dataField] is a Boolean and will reflect 
that value.  If you want anything else, you'll need to bake a subclass upfront 
with the flexibility to do what you want.  ItemRenderers are classes and you 
can't define classes at runtime, you can only tweak properties and styles.

Alex Harui
Flex SDK Developer
Adobe Systems Inc.<http://www.adobe.com/>
Blog: http://blogs.adobe.com/aharui

From: flexcoders@yahoogroups.com [mailto:flexcod...@yahoogroups.com] On Behalf 
Of Penny Laus
Sent: Thursday, April 02, 2009 12:52 AM
To: flexcoders@yahoogroups.com
Subject: [flexcoders] Defining item renderers for a DataGrid using ActionScript


I'm trying to create item renderers for DataGrid columns dynamically
at runtime and am having a hard time sorting out how to define and
attach item renderers. To make sure I've got the mecahnics right
first, all I'm trying for now is to make a non-editable column display
as a checkbox. My column definitions are stored in an XML file - the
snipped below shows how I'm reading the definitions and creating the
DataGrid's columns:

for each (var columnDefinition:XML in columnDefinitionsXmlList) {
var newColumn:DataGridColumn = new DataGridColumn;
newColumn.headerText = columnDefinition.col_title;
newColumn.dataField = columnDefinition.col_data;
newColumn.width = Number(columnDefinition.col_width);
if (columnDefinition.col_type == "boolean") {
// newColumn.itemRenderer = new ClassFactory(mx.controls.CheckBox);
var cb:ClassFactory = new ClassFactory(mx.controls.CheckBox);
newColumn.itemRenderer = cb;
}

columnDefinitions.push(newColumn);
}

The code shown above does make the column display as a checkbox - but
there's no code to turn the checkbox on/off depending on the current
cell's value. In the example above, the variable cb is the checkbox
that is then associated with the column. What I don't see in
FlexBuilder's hinting system is any property of cb that lets me set
the condition that controls if the checkbox is on or off - or any of
the other properties normally used for an item renderer defined
through MXML.

Am I missing something obvious or am I going about this in the wrong way?

Links to any relevant examples appreciated - I've looked at a lot of
examples, but have yet to find one that shows defining an item
renderer in quite this way. I'm happy to create a class or component
for CheckBox (or whatever else) so long as I'll then be able to set
the condition which controls on/off.

Thanks for any help.