小编Tim*_*yse的帖子

在我的DbContext子类中,我重写了SaveChanges()方法,因此我可以实现一种类似触发器的功能(在实际保存更改之前).现在,在某些触发器中,有必要检测某些关系是否已经改变,无论多对多,一对一/零等.

我已经阅读了互联网上的一些帖子,包括本网站上的一些帖子,提到DbContext API没有公开任何获取关系信息的方法.但是,ObjectContext应该能够.

我的SaveChanges方法:

public override int SaveChanges()
{
    IEntity entity;
    ChangeTracker.DetectChanges();

    var stateManager = ((IObjectContextAdapter)this).ObjectContext.ObjectStateManager;
    var added = stateManager.GetObjectStateEntries(EntityState.Added).ToList();
    var updated = stateManager.GetObjectStateEntries(EntityState.Modified).ToList();
    var deleted = stateManager.GetObjectStateEntries(EntityState.Deleted).ToList();
    var unchanged = stateManager.GetObjectStateEntries(EntityState.Unchanged).ToList();

    while ((entity = _entitiesRequiringTriggering.FirstOrDefault(x => x.Value).Key) != null)
    {
        _entitiesRequiringTriggering[entity] = false;
        var entry = ChangeTracker.Entries<IEntity>().SingleOrDefault(x => x.State != EntityState.Unchanged && x.Entity == entity);
        if (entry == null) continue;
        var trigger = Triggers.Triggers.GetTriggerForEntity(entry.Entity, this);
        if (trigger == null) continue;
        trigger.BeforeSave(entry.Entity);
        switch (entry.State)
        {
            case EntityState.Added:
                trigger.BeforeAdd(entry.Entity);
                break;
            case …