Problem with datagrid dataprovider

Question

I'm wondering why is it my search result is null after I press search button. After I press search, the datagrid is blank. But I ever test my service and it's working.
Anyone has any idea how to solve it? So sorry I'm totally new to FLEX... >.<
Below is my code...
<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
                       xmlns:s="library://ns.adobe.com/flex/spark"
                       xmlns:mx="library://ns.adobe.com/flex/mx"
                       xmlns:productbasicservice="services.productbasicservice.*"
                       width="1024" height="768">
    <fx:Script>
        <![CDATA[
            import mx.collections.ArrayCollection;
            import mx.controls.Alert;
            import mx.controls.TextInput;
            import mx.events.DataGridEvent;
            import mx.events.FlexEvent;
            import mx.rpc.AsyncToken;
            import valueObjects.Product_basic;
            protected function dataGrid_creationCompleteHandler(event:FlexEvent):void
                getProduct_basic_pagedResult.token = productbasicService.getProduct_basic_paged();
            protected function saveClick(event:MouseEvent):void
                productbasicService.commit();
            protected function revertData(event:MouseEvent):void
                productbasicService.revertChanges();
            protected function searchData(event:MouseEvent):void
                var searchStr:String = searchbox.toString();
                searchProduct_basicResult.token = productbasicService.searchProduct_basic(searchStr);
                dataGrid.dataProvider = searchProduct_basicResult.lastResult;
        ]]>
    </fx:Script>
    <fx:Declarations>
        <s:CallResponder id="getAllProduct_basicResult"/>
        <productbasicservice:ProductbasicService id="productbasicService"
                                                 fault="Alert.show(event.fault.faultString + '\n' + event.fault.faultDetail)"
                                                 showBusyCursor="true"/>
        <s:CallResponder id="getProduct_basic_pagedResult"/>
        <s:CallResponder id="searchProduct_basicResult"/>
        <!-- Place non-visual elements (e.g., services, value objects) here -->
    </fx:Declarations>
    <mx:DataGrid id="dataGrid" x="11" y="61" width="1003" height="557"
                 creationComplete="dataGrid_creationCompleteHandler(event)"
                 dataProvider="{getProduct_basic_pagedResult.lastResult as ArrayCollection}" editable="true">
        <mx:columns>
            <mx:DataGridColumn width="200" dataField="id" editable="false" headerText="ID"/>
            <mx:DataGridColumn dataField="name" headerText="name"/>
            <mx:DataGridColumn width="200" dataField="price" headerText="Price"/>
            <mx:DataGridColumn dataField="description" headerText="description"/>
        </mx:columns>
    </mx:DataGrid>
    <s:Button x="849" y="22" label="Save" click="saveClick(event)"/>
    <s:Button x="944" y="22" label="Revert" click="revertData(event)"/>
    <s:TextInput x="14" y="22" width="367" id="searchbox"/>
    <s:Button id="button" x="389" y="22" label="Search" click="searchData(event)"/>
</s:WindowedApplication>
I have added my own data service operation in the php file called searchProduct_basic(searchStr). Basically this function return the object of the search result.

Answer 1

It's the same for lastResult as ArrayCollection.
            protected function searchData(event:MouseEvent):void
                var searchStr:String = searchbox.toString();
                searchProduct_basicResult.token = productbasicService.searchProduct_basic(searchStr);
                dataGrid.dataProvider = searchProduct_basicResult.lastResult;
For you information, the searchProduct_basic(searchStr) would return Product_basic object. >.<