Help! why the value does not change?

Question

in ViewStack at index=0 (home page) , I pass object to placements (index=1) when I click on a datagrid item.  The name on placements has the value that passed from home page.
when I return to home page and click on another item on datagrid, I want the new value pass to placements page, but the first item data is still on the placements. How to refresh it?
I need the value (text) of
TextInput id="txtName"  on placement page changes as I assign at home page.
See below
[Bindable] public var objPlacementMain:Object = new Object;      
private  function gotoPlacements(event:ListEvent):void{   this.objPlacementMain.name = this.dg.selectedItem.col1;
this.homePlacement.selectedIndex = 1;
<mx:ViewStack id="homePlacement">
<mx:V
<mx:DataGrid id="dg" itemClick="gotoPlacements(event)">
<mx:columns>
 <mx:DataGridColumn headerText="Column 1" dataField="col1"/>
 <mx:DataGridColumn headerText="Column 2" dataField="col2"/>
 <mx:DataGridColumn headerText="Column 3" dataField="col3"/>
 </mx:columns>
</mx:DataGrid>
<h:placements
objPlacement="{objPlacementMain}" />
</mx:ViewStack>
at placements
[Bindable] public var objPlacement:Object = new Object;
<mx:HBox   
width="100%" height="30">
<mx:Spacer width="48" height="25"/>
<mx:Label text="Name " fontWeight="bold" width="51"/> <mx:TextInput id="txtName" text="{this.objPlacement.name }" width="193" editable="false"/>
</mx:HBox>

Answer 1

Flex harUI ,
Thank you very much. I forgot key word [Bindable].
It works after I add it.