Question

我创建了一个可扩展性方法，用于删除一个名为Reservation的Linq To Sql对象。

嗯，在我创建的这个部分方法中，我想更新一些其他对象。我似乎无法将更新保留在数据库中。这是我删除预订的部分方法。

public partial class LawEnforcementDataContext
{

    partial void DeleteReservation(Reservation instance)
    {
        // Get ID's of those seated in course
        var roster = new Roster(this, instance.CourseID);
        var seated = from r in roster.All
                     where r.WaitingList == false
                     select r.ID;

        // delete the reservation
        this.ExecuteDynamicDelete(instance);

        // get seated id's not in original seated ids
        var newlySeated = from r in roster.All
                          where r.WaitingList == false && !seated.Contains(r.ID)
                          select r.ID;

        var reservations = this.Reservations.Where(r => newlySeated.Contains(r.ID));

        foreach (var r in reservations)
        {
            r.Confirmed = false;
            // Have tried doing nothing, thinking calling code's db.SubmitChanges() would do the trick
            //this.ExecuteDynamicUpdate(r); HAVE TRIED THIS
        }
        //this.SubmitChanges(); HAVE TRIED THIS
    }
}

删除正在进行，但更新不是。在最后几行中评论了我尝试过的一些事情。

有什么想法吗？谢谢！

修改

以下是我为解决这个问题所做的工作：

   public override void SubmitChanges(System.Data.Linq.ConflictMode failureMode)
{
    ChangeSet delta = GetChangeSet();

    foreach (var res in delta.Deletes.OfType<Reservation>())
    {
        // Get ID's of those seated in course
        var roster = new Roster(this, res.CourseID);
        var seated = from r in roster.All
                     where r.WaitingList == false
                     select r.ID;

        base.SubmitChanges(failureMode);

        // get seated id's not in original seated ids
        var newlySeated = from r in roster.All
                          where r.WaitingList == false && !seated.Contains(r.ID)
                          select r.ID;

        var reservations = this.Reservations.Where(r => newlySeated.Contains(r.ID));

        foreach (var r in reservations)
        {
            r.Confirmed = false;
        }
    }

    base.SubmitChanges(failureMode);
}

Answer 1

我希望这里的问题是它已经调用了GetChangeSet()。

我建议你在数据上下文中覆盖SubmitChanges()，然后在那里应用这个逻辑......

partial class LawEnforcementDataContext
{
    public override void SubmitChanges(
        System.Data.Linq.ConflictMode failureMode)
    {
        ChangeSet delta = GetChangeSet();
        foreach (var reservation in delta.Deletes.OfType<Reservation>())
        {
            // etc
        }
        base.SubmitChanges(failureMode);
    }
}

Answer 2

以下是更新部分类中对象的解释和好方法： Implementing linqtosql partial DataContext class - how to inspect before/after values

我希望它有所帮助。

LINQ to SQL - 更新部分类中的数据上下文对象

2 个答案: