public static void UpdateModel
     
      (T entity, DbContext db) where T : class        {            db.Set
      
       ().Attach(entity);            foreach (System.Reflection.PropertyInfo p in entity.GetType().GetProperties())            {                if (p.GetValue(entity) != null)                {                    db.Entry(entity).Property(p.Name).IsModified = true;                }            }            db.SaveChanges();        }