How to get id from entity for Auditlog in Entity Framework 6

Question

I know it\'s several similar posts out there, but I cannot find any with a solution to this issue.

I want to add a (sort of) AudioLog when adding, changing or deleting e

Answer 1

Ahhh... Off course!! The id will only be a "problem" for the entities that are newly added, so by splitting the list into two (one for modified/deleted and one for added), I create the AuditLog in two stages.

For anyone else who want to apply this kind of AuditLog, here is my working code:

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);
    }
}