extract data from advancedDataGrid. Please help.

I know http://forums.adobe.com/thread/131416 has the answer inside but i dont understand what it means (hierarchy and cursor thingies) and how to use it. I only manage to understand until the getting selected index, and I got it. But I dont know how to use it to extract the data from that row and trace it out. please help me add on to my doubleClickHandler function. These are my codes.

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my xml file.

<location locations="Singapore">

<locations Region="north">
<details l_id="7" l_title="Causeway Point" street="1 Woodlands Square, #01-39 Causeway Point"/>
<details l_id="17" l_title="IMM Building" street="2 Jurong East Street 21, #01-51"/>
</locations>

<locations Region="west">
<details l_id="4" l_title="Arena Country Club " street="511 Upper Jurong Road, #01-06"/>
<details l_id="19" l_title="Jurong Point" street=" 63 Jurong West Central 3 #B1-54/55 Jurong Point"/>
</locations>
</location>


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my actionscript code in the main mxml file

private function doubleClickHandler():void
{
var item:Object = agd.selectedItem;
var index:int = agd.selectedIndex;

if (!item || index == -1)
return ;
Alert.show("Double Clicked item index:" + index);
}


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<mx:AdvancedDataGrid id="agd"
doubleClickEnabled="true" itemDoubleClick="doubleClickHandler()">
<mx:columns>
<mx:AdvancedDataGridColumn dataField="@locations"
headerText="Location"/>
<mx:AdvancedDataGridColumn dataField="@l_title"
headerText="Title"/>
<mx:AdvancedDataGridColumn dataField="@l_street"
headerText="Street"/>
</mx:columns>
</mx:AdvancedDataGrid>

The "item" variable in the "doubleClickHandler" function should contain the object with the row you double-clicked on. You can trace it out like so:

import mx.utils.ObjectUtil;
trace(ObjectUtil.toString(item));