Question

我知道那里有几个类似的帖子，但我找不到任何解决这个问题的方法。

我想在Entity Framework 6中添加，更改或删除实体（软删除）时添加（某种）AudioLog。我已经重写了SaveChanges，因为我只想为EntityStates添加，修改日志条目或删除，我在第一次调用SaveChanges之前获取列表。问题是，因为我需要记录已执行的操作，我需要检查实体的EntityState。但是在调用SaveChanges之后，所有条目的EntityState都是Unchanged。

public override int SaveChanges()
{
    using (var scope = new TransactionScope())
    {
        var modifiedEntries = ChangeTracker.Entries()
            .Where(e => e.State == EntityState.Added || e.State == EntityState.Deleted || e.State == EntityState.Modified)
            .ToList();

        int changes = base.SaveChanges();
        foreach (var entry in modifiedEntries)
        {
            ApplyAuditLog(entry);
        }

        base.SaveChanges();
        scope.Complete();
        return changes;
    }
}

private void ApplyAuditLog(DbEntityEntry entry)
{
    ILog entity = entry.Entity as ILog;

    if (entity != null)
    {
        LogOperation operation;
        switch (entry.State)
        {
            case EntityState.Added:
                operation = LogOperation.CreateEntity;
                break;
            case EntityState.Deleted:
                operation = LogOperation.DeleteEntity;
                break;
            case EntityState.Modified:
                operation = LogOperation.UpdateEntity;
                break;
            default:
                throw new ArgumentOutOfRangeException();
        }

        AuditLog log = new AuditLog
        {
            Created = DateTime.Now,
            Entity = entry.Entity.GetType().Name,
            EntityId = entity.Id,
            Operation = operation,
        };

        AuditLog.Add(log);
    }
}

Answer 1

啊......当然!!对于新添加的实体，id只是一个“问题”，因此通过将列表拆分为两个（一个用于修改/删除，一个用于添加），我分两个阶段创建AuditLog。

对于其他想要应用此类AuditLog的人，这是我的工作代码：

public override int SaveChanges()
{
    using (var scope = new TransactionScope())
    {
        var addedEntries = ChangeTracker.Entries().Where(e => e.State == EntityState.Added).ToList();
        var modifiedEntries = ChangeTracker.Entries().Where(e => e.State == EntityState.Deleted || e.State == EntityState.Modified).ToList();

        foreach (var entry in modifiedEntries)
        {
            ApplyAuditLog(entry);
        }

        int changes = base.SaveChanges();
        foreach (var entry in addedEntries)
        {
            ApplyAuditLog(entry, LogOperation.CreateEntity);
        }

        base.SaveChanges();
        scope.Complete();
        return changes;
    }
}

private void ApplyAuditLog(DbEntityEntry entry)
{
    LogOperation operation;
    switch (entry.State)
    {
        case EntityState.Added:
            operation = LogOperation.CreateEntity;
            break;
        case EntityState.Deleted:
            operation = LogOperation.DeleteEntity;
            break;
        case EntityState.Modified:
            operation = LogOperation.UpdateEntity;
            break;
        default:
            throw new ArgumentOutOfRangeException();
    }

    ApplyAuditLog(entry, operation);
}

private void ApplyAuditLog(DbEntityEntry entry, LogOperation logOperation)
{
    ILog entity = entry.Entity as ILog;

    if (entity != null)
    {
        AuditLog log = new AuditLog
        {
            Created = DateTime.Now,
            Entity = entry.Entity.GetType().Name,
            EntityId = entity.Id,
            Operation = logOperation,
        };
        AuditLog.Add(log);
    }
}

Answer 2

您可以将 EntityState 保存到 Entity 键值对，并在第一次更改后使用它。

var 条目 = this.ChangeTracker.Entries() .Where(e => e.State == EntityState.Added || e.State == EntityState.Modified || e.State == EntityState.Deleted) .Select(e => new { e.State, e }).ToList();

如何从Entity Framework 6中的Auditlog实体获取id

2 个答案: