c# - DevExpress eXpressApp——数据库更新

Question

我目前正在使用 DevExpress 的 eXpressApp。我想知道如何在租用视频时触发客户表的更新，以及可能是一个rentalHistory 表？我需要用代码来做吗？或者我可以创建触发器或查询，当调用 CommitChanges() 时可以自动调用

 public class Rent : VideoRentBaseObject {
        MovieItem item;
        int days;
        DateTime? returnedOn;
        Receipt receipt;
        Receipt receiptOverdue;
        decimal payment;
        decimal overduePayment;

        public Rent(Session session) : base(session) { }
        public Rent(Session session, int selfId)
            : this(session) {
            SelfId = selfId;
        }
        public Rent(Receipt receipt, MovieItem item) : this(receipt, item, 0) { }
        public Rent(Receipt receipt, MovieItem item, int days)
            : this(receipt.Session) {
            if(receipt == null) throw new ArgumentNullException("Receipt");
            if(item == null) throw new ArgumentNullException("Item");
            if(item.Status != MovieItemStatus.Active) throw new ArgumentException("Item is not active");
            Receipt = receipt;
            Item = item;
            if(receipt.Type == ReceiptType.Purchases) {
                Item.Status = MovieItemStatus.Sold;
                Item.AvailableForSell = false;
                Days = 0;
            } else {
                Item.Status = MovieItemStatus.Rented;
                Days = days != 0 ? days : item.Movie.Category.GetPrice(item.Format).DefaultRentDays;
            }
        }
        public override void AfterConstruction() {
            base.AfterConstruction();
            Days = 1;
        }
}

Answer 1

您可以覆盖 Rent 类的 onSaving() 方法，您可以在其中放入一些逻辑，在关联的 Client 对象中进行更改，保存它，在保存租金更改之前或之后。