void removeExpiredRows(DataTable table, string expiredColumnName) {
string filter = string.Format(CultureInfo.InvariantCulture, "{0} < #{1}#",
expiredColumnName, DateTime.Now);
DataView view = new DataView(table, filter, null, DataViewRowState.CurrentRows);
for (int i = view.Count - 1; i >= 0; i--)
view.Delete(i);
}