thanks, this is my scripts:
[Bindable]
private var ws:WSInterfaceService = new WSInterfaceService();
...
public function showDocs():void
{
// Webservice function call
ws.getDocs();
//set the result to a dataProvider in runtime, its not work!
but if direct use the bindable link in <mx

ataGrid>, then no such problem.
//dg.dataProvider = ws.getDocs_lastResult;
}
...
<mx

ataGrid width="100%" id="dg" dataProvider="{ws.getDocs_lastResult}">
<mx:columns>
<mx

ataGridColumn dataField="name" headerText="Name"/>
<mx

ataGridColumn dataField="size" headerText="Size"/>
<mx

ataGridColumn dataField="changedDate" headerText="Changed
Date"/>
<mx

ataGridColumn labelFunction="showURL" headerText="URL"/>
</mx:columns>
</mx

ataGrid>
...
<mx:ControlBar horizontalAlign="center">
<mx:Button label="Get date from server" click="showDocs()"/>
...