public class OrderLineFieldGroupRelation 

class MyPage : System.Web.UI.Page
{
 
    private void SaveGroupOrderlineRelations()
    {
     	//Save Orderline field relations. First delete all, then save.
     	OrderLineFieldGroupRelation.DeleteAll(groupId);
     	int rowCount = Base.ChkInteger(Base.Request["OrderLineFieldCount"]);
     	for (int i = 0; i < rowCount; i++)
     	{
     		string fieldSystemName = Base.ChkString(Base.Request[string.Format("OrderLineFieldHidden_{0}", i)]);
     		if (fieldSystemName != "")
     		{
     			OrderLineFieldGroupRelation relation = new OrderLineFieldGroupRelation(fieldSystemName, groupId);
     			relation.Save();
     		}
     	}
     	grp.ClearOrderLineFieldCache();
    }
}