var data: ArrayCollection = new ArrayCollection(
            [
                { name: "ProductA",user: {login: "loginA",email: "emailA"} },{ name: "ProductB",user: {login: "loginB",email: "emailB"} },{ name: "ProductC",user: {login: "loginC",email: "emailC"} }
            ]
        );

这个数组是我的AdvancedDataGrid的数据提供者：

<mx:AdvancedDataGrid dataProvider="{data}">
    <mx:columns>
        <mx:AdvancedDataGridColumn headerText="Product" width="55" dataField="name" /> 
        <mx:AdvancedDataGridColumn headerText="User" dataField="user.login" />
        <mx:AdvancedDataGridColumn headerText="Email" dataField="user.email" />
    </mx:columns>
</mx:AdvancedDataGrid>

问题是 – AdvancedDataGrid不显示嵌套的User对象的属性,但是简单的DataGrid会显示.
这有什么不对？