Drag an Drop and Cursors

Question

I have three lists, each one filled with xml data through an arraycollection.
Below those lists i have a datagrid. People can drag items from those lists to the datagrid.
The datagrid consists of three columns: Product, Price and Pieces.
When people drag the same item from those lists i want to count them and show the result in the third column
of the datagrid.
I tried to use a cursor to count the same items and show the result in the third column of the datagrid, but i don't know
behind which event i have to put this function:
private  
function aantalpizza():void{ 
cursor = acaantal.createCursor();
var pizzaobject:Object = {item:mypizzas.selectedItem.item}; 
if(cursor.findAny(pizzaobject)){
cursor.current.aantal ++
elsemypizzas.selectedItem.aantal = 1;
Does anyone have an idea?

Answer 1

i tried the following code:
private  
function aantalpizza(ev:DragEvent):void{ 
cursor =
acaantal.createCursor(); 
var pizzaobject:Object = {item:mypizzas.selectedItem.item}; 
if(cursor.findAny(pizzaobject)){
cursor.current.aantal ++
elsemypizzas.selectedItem.aantal = 1;
<mx:DataGrid  dragComplete="aantalpizza(event)" dataProvider="{acaantal}" id="dgbestelling" dropEnabled="true">
 <mx:columns>
 <mx:DataGridColumn dataField="item" headerText="Artikel" resizable="false" width="150"/>
 <mx:DataGridColumn dataField="prijs" headerText="Prijs"/>
 <mx:DataGridColumn dataField="aantal" headerText="Aantal"/>
 </mx:columns>
 </mx:DataGrid>
it didn't work, i need the datafield "aantal" to update if the same item is being dragged to the datagrid
==> "aantal" means quantity, so if the same item is being dragged , it needs to count the quantity.