public static bool Update<U>(U dContext, int iCurrentUserId)
        where U : DbContext
    {
        using (var tx = dContext.Database.BeginTransaction())
        {
            try
            {
                foreach (T tItem in dContext.Set<T>())
                {
                    if (dContext.Entry(tItem).State != EntityState.Modified) continue;
                    ModificationSet(tItem, iCurrentUserId);
                }
                dContext.SaveChanges();
                tx.Commit();
                return true;
            }
            catch (Exception e)
            {
                tx.Rollback();
                return false;
            }
        }
    }

foreach (T tItem in dContext.Set<T>().Where(z => dContext.Entry(z).State == EntityState.Modified))

foreach (T tItem in dContext.ChangeTracker.Entries<T>().Where(z => z.State == EntityState.Modified).Select(z => z.Entity))