//Silme fonksiyonu
 public void Delete(GeneralBooks generalBooks)
 {
     using (InstituteDbEntities context = new InstituteDbEntities())
     {
         var entity = context.Entry(generalBooks);
         entity.State = EntityState.Deleted;
         context.SaveChanges();
     }
 }
        //Ekleme fonksiyonu
        public void Add(GeneralBooks generalBooks)
        {
            using (InstituteDbEntities context = new InstituteDbEntities())
            {
                var entity = context.Entry(generalBooks);
                entity.State = EntityState.Added;
                context.SaveChanges();

                //context.GeneralBooks.Add(generalBooks);
                //context.SaveChanges();
            }
        }