Null value in in ItemCommand()

[Xavier Pacheco]

I have a DataList that is bound to an ArrayLis of objects of the type EventInfo. In the ItemCommand event
for this datalist is:

private void DataList1_ItemCommand(object source, System.Web.UI.WebControls.DataListCommandEventArgs e)
{
if ( e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
{
if ( e.CommandName == "REGISTER" )
{
DropDownList ddl = (DropDownList)e.Item.FindControl( "DropDownList1" );
int EventInstanceID = Int32.Parse( ddl.SelectedValue );
EventInfo ei = (EventInfo)e.Item.DataItem;

decimal amount = ei.Price;
Session["Amount"] = amount;
Session["EventInstanceID"] = EventInstanceID;
}
}
}

any idea why

EventInfo ei = (EventInfo)e.Item.DataItem;

turns up null?

-- xavier