<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" creationComplete="init()"
    width="400" height="400">
<mx:Script>
    <![CDATA[
        import mx.collections.ArrayCollection;
        import mx.controls.Alert;
        
        private function init():void{
            
        }
        [Bindable]
        private var acData:ArrayCollection = new ArrayCollection([
                                                                {title:'myTitle 1',test_id:1,description:'my description something'},
                                                                {title:'myTitle 2',test_id:2,description:'my description something else'}
                                                                ]);
                                                                
        public function getDetails(id:Number):void{
            Alert.show('You clicked the row with an ID of: ' + id);
        }
    ]]>
</mx:Script>

<mx:DataGrid id="subLevelGrid" dataProvider="{acData}" width="100%" height="100%">
    <mx:columns>
        <mx:DataGridColumn headerText="Title" dataField="title" />
        <mx:DataGridColumn headerText="" dataField="test_id" width="80">
            <mx:itemRenderer>
                <mx:Component>
                    <mx:HBox horizontalAlign="center">
                        <mx:Button label="Details" width="75" click="outerDocument.getDetails(data.test_id)"/>    
                    </mx:HBox>                                            
                </mx:Component>
            </mx:itemRenderer>
        </mx:DataGridColumn>
    </mx:columns>
</mx:DataGrid>
</mx:Application>