我的OperationContract:publicListGetMessages(){Listmessages=newList();foreach(Messagemin_context.Messages.ToList()){messages.Add(newMessageDTO(){MessageID=m.MessageID,Content=m.Content,Date=m.Date,HasAttachments=m.HasAttachments,MailingListID=(int)m.MailingListID,SenderID=(int)m.SenderID,Subject=m.