LINQ to SQL-更新局部类中的数据上下文对象 [英] LINQ to SQL - Updating Data Context Objects in Partial Classes

问题描述

我已经创建了一种可扩展性方法，用于删除我的Linq To Sql对象之一，称为保留.

I have created an extensibility method for deleting one of my Linq To Sql objects called Reservation.

好吧，在我创建的这种局部方法中，我想更新一些其他对象.我似乎无法使更新保留在数据库中.这是我删除预订的部分方法.

Well, in this partial method I created, I want to update some other objects. I can't seem to get the update to be persisted in the database. Here is my partial method for deleting the reservation.

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
    }
}

正在删除，但没有进行更新.在最后几行中评论了我尝试过的一些事情.

The delete is taking place but the update is not. Commented in the last few lines are some of the things I have tried.

有什么想法吗?谢谢！

编辑

这是我为解决此问题所做的事情:

Here is what I have done to solve this:

   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);
}

推荐答案

我希望这里的问题是它已经调用了GetChangeSet().

I expect the problem here is that it has already called GetChangeSet().

我建议您在数据上下文中覆盖SubmitChanges()，并在此应用此逻辑...

I suggest you override SubmitChanges() at the data-context, and apply this logic there instead...

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);
    }
}

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