cannot use DataRowView in ONItemBound event if datagrid datasource is Datareader?

[rockdale]

private void dgrid_OnItemDataBound(object sender,
System.Web.UI.WebControls.DataGridItemEventArgs e)
{
if(e.Item.ItemType ==ListItemType.Item||e.Item.ItemType
==ListItemType.AlternatingItem)
DataRowView drv = (DataRowView)e.Item.DataItem;


it caught error.

but if I change the datasource to DataTable then it is ok.

Is it true we cannot use DataRowView in ONItemBound event if datagrid
datasource is Datareader?

thanks
-Rockdale