[SerializableAttribute()] 
public class OrderFieldCollection : System.Collections.ObjectModel.Collection<OrderField> 

class MyPage : System.Web.UI.Page
{
   public OrderFieldCollection GetOrderFields()
   {
       if (HttpContext.Current.Application["Ecom:OrderFields"] == null)
       {
           OrderFieldCollection ofc = OrderField.getOrderFields();
           foreach (OrderField of in ofc)
           {
               of.Lock();
           }
           HttpContext.Current.Application.Lock();
           HttpContext.Current.Application.Set("Ecom:OrderFields", ofc);
           HttpContext.Current.Application.UnLock();
           return ofc;
       }
       else
       {
           return (OrderFieldCollection)HttpContext.Current.Application["Ecom:OrderFields"];
       }
   }
}

public static OrderFieldCollection GetOrderFields()
{
    string sql = "SELECT * FROM EcomOrderField ORDER BY OrderFieldSort";

 	OrderFieldCollection orderFields = new OrderFieldCollection();
   	using (IDataReader dataReader = Database.CreateDataReader(sql, "Ecom.mdb"))
   	{
   		while (dataReader.Read())
   		{
   			orderFields.Add(new OrderField(dataReader));
   		}
   	}
   	return orderFields;
   }