Flexでdatagridに右クリックメニュー項目を追加して具体的に実現します。

 
<?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" 
creationComplete="initApp()"> 
<s:layout> 
<s:HorizontalLayout horizontalAlign="center" verticalAlign="middle"/> 
</s:layout> 
<fx:Script> 
<![CDATA[ 
import mx.controls.Alert; 
import mx.events.DataGridEvent; 
import mx.events.FlexEvent; 

import spark.events.GridEvent; 
private var myContextMenu:ContextMenu; 

private function initApp():void 
{ 
popUpMenu(); 
} 

private function popUpMenu():void 
{ 
myContextMenu = new ContextMenu(); 
removeDefaultItems(); 
addCustomMenuItems(); 
//             
myContextMenu.addEventListener(ContextMenuEvent.MENU_SELECT, menuSelectedHandler); 
myDataGrid.contextMenu = myContextMenu; 
} 
//        
private function removeDefaultItems():void 
{ 
myContextMenu.hideBuiltInItems(); 
var defaultItems:ContextMenuBuiltInItems = myContextMenu.builtInItems; 
defaultItems.print = false; 
} 
//           
private function addCustomMenuItems():void 
{ 
var item:ContextMenuItem = new ContextMenuItem("   "); 
//       
item.visible = false; 
myContextMenu.customItems.push(item); 
//            
item.addEventListener(ContextMenuEvent.MENU_ITEM_SELECT, itemSelectedHandler); 
} 
//             
private function menuSelectedHandler(event:ContextMenuEvent):void 
{ 
var item:ContextMenuItem = myContextMenu.customItems[0] as ContextMenuItem; 

if (myDataGrid.selectedIndex >= 0) 
{ 
item.visible = true; 
} 
else 
{ 
item.visible = false; 
} 
} 
//              
private function itemSelectedHandler(event:ContextMenuEvent):void 
{ 

if (myDataGrid.selectedIndex >= 0) 
{ 
myDataGrid.dataProvider.removeItemAt(myDataGrid.selectedIndex); 
} 
} 

]]> 
</fx:Script> 
<s:DataGrid requestedRowCount="4" id="myDataGrid" 
width="500"> 
<s:columns> 
<s:ArrayList> 
<s:GridColumn dataField="dataField1" headerText="  1" id="col1"></s:GridColumn> 
<s:GridColumn dataField="dataField2" headerText="  2"></s:GridColumn> 
<s:GridColumn dataField="dataField3" headerText="  3"></s:GridColumn> 
</s:ArrayList> 
</s:columns> 
<s:typicalItem> 
<fx:Object dataField1="    " dataField2="    " dataField3="    "></fx:Object> 
</s:typicalItem> 
<s:ArrayList> 
<fx:Object dataField1="  1" dataField2="  1" dataField3="  1"></fx:Object> 
<fx:Object dataField1="  2" dataField2="  2" dataField3="  2"></fx:Object> 
<fx:Object dataField1="  3" dataField2="  3" dataField3="  3"></fx:Object> 
<fx:Object dataField1="  4" dataField2="  4" dataField3="  4"></fx:Object> 
</s:ArrayList> 
</s:DataGrid> 

</s:Application>