spark DataGrid - how to dynamically change itemRenderer colors in code

Update: Modified the code a bit more...

Thank you Carol for pointing me in the right direction!   A combination of the IGridItemRenderer.prepare() with the ClassFactory.properties did the trick!  Now I can change the item renderer's properties on the fly via code and have the colors be driven via logic, or an XML file.

Here is a sample application that I modified to show how it works...

******************************************************************
** THE MAIN APPLICATION CODE
**
** Create a new application and paste this in
** File->New->MXML Application
******************************************************************

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
      xmlns:s="library://ns.adobe.com/flex/spark"
      xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600">
<fx:Declarations>
  <s:ArrayCollection id="productInfo">
   <fx:Object product="Winnie the Pooh" inStock="false" price="19.99" />
   <fx:Object product="Dora the Explorer" inStock="true" price="24.99" />
   <fx:Object product="Elmo" inStock="true" price="29.99" />
   <fx:Object product="Olivia the Pig" inStock="true" price="12.66" />
   <fx:Object product="Little People" inStock="true" price="25.99" />
   <fx:Object product="Sophie Giraffe" inStock="false" price="9.99" />
   <fx:Object product="Snoopy" inStock="true" price="6.55" />
  </s:ArrayCollection>
 
  <s:ArrayList id="columns1" >
   <s:GridColumn headerText="Product" dataField="product" itemRendererFunction="MyCustomItemRendererFunction" />
   <s:GridColumn headerText="Price" dataField="price" itemRendererFunction="MyCustomItemRendererFunction"/>
   <s:GridColumn headerText="In Stock?" dataField="inStock" itemRendererFunction="MyCustomItemRendererFunction" />
  </s:ArrayList>
 
</fx:Declarations>

<fx:Script>
  <![CDATA[
   import mx.core.ClassFactory;
   import spark.skins.spark.DefaultGridItemRenderer;
  
   private var varDefaultBackgroundColor:uint = 0xFFFFFF;
   private var varDefaultForegroundColor:uint= 0x000000;
  
   private var varPriceBackgroundColor:uint= 0xFF0000;
   private var varPriceForegroundColor:uint= 0xFFFFFF;
  
     
   private function MyCustomItemRendererFunction(item:Object, column:GridColumn):ClassFactory
   {
   
    // Create a Class Factory variable
    var myRendererObject:ClassFactory;
   
    // This is the "default" color is nothing else happens
    // I'm passing it a pointer to "MyItemRenderer"
    myRendererObject = new ClassFactory(MyItemRenderer);
    myRendererObject.properties = { MyBackgroundColor: varDefaultBackgroundColor, MyForegroundColor: varDefaultForegroundColor };
   
    if (column.dataField == "price")
    {
     // override the renderer and set a diffent color "in code" using a variable
     myRendererObject.properties = { MyBackgroundColor: varPriceBackgroundColor, MyForegroundColor: varPriceForegroundColor };
    }
   
       
    return myRendererObject;
   
   }
  
  ]]>
</fx:Script>

<s:DataGrid id="ProductGrid" dataProvider="{productInfo}" columns="{columns1}" width="360"/>

</s:Application>

*******************************************************************************
** MyItemRenderer CODE
**
** Create a new item renderer called "MyItemRenderer" and paste this in
** File->New->Item Renderer
**
*******************************************************************************

<?xml version="1.0" encoding="utf-8"?>
<s:GridItemRenderer xmlns:fx="http://ns.adobe.com/mxml/2009"
     xmlns:s="library://ns.adobe.com/flex/spark"
     xmlns:mx="library://ns.adobe.com/flex/mx" clipAndEnableScrolling="true">

<fx:Script>
  <![CDATA[
  
   public var MyBackgroundColor:uint;
   public var MyForegroundColor:uint;
     
   override public function prepare(hasBeenRecycled:Boolean):void
   {
    MyFillColor.color = MyBackgroundColor;
    MyTextColor.text = data[column.dataField];
    MyTextColor.setStyle("color", MyForegroundColor);
   }
  
  ]]>
</fx:Script>
<s:Rect top="0" bottom="0" right="0" left="0">
  <s:fill>
   <s:SolidColor id="MyFillColor" alpha=".5"/>
  </s:fill>
</s:Rect>
<s:Label id="MyTextColor" top="9" left="7" alpha="1"/>

</s:GridItemRenderer>

You should be able to pass the color to the renderer something like

myHeaderRenderer.properties = ;

And inside force a repaint accordingly. Did not try it myself though.

C