// private static List<Aluno> alunos = new List<Aluno>();

        public void inserir(Matricula obj)
        {
            using (since2013bdEntities db =
                       new since2013bdEntities())
            {
                db.Matriculas.Add(obj);
                db.SaveChanges();
            }
        }
        // private static List<Aluno> alunos = new List<Aluno>();

        public void inserir(Aluno obj)
        {
            using (since2013bdEntities db =
                       new since2013bdEntities())
            {
                db.Alunos.Add(obj);
                db.SaveChanges();
            }
        }
 public void inserir(Disciplina obj)
 {
     using (since2013bdEntities db =
                new since2013bdEntities())
     {
         db.Disciplinas.Add(obj);
         db.SaveChanges();
     }
 }
 public void excluir(Aluno alu)
 {
     using (since2013bdEntities db =
                new since2013bdEntities())
     {
         //alterar status para excluido
         db.Entry(alu).State =
             System.Data.Entity.EntityState.Deleted;
         //salvar
         db.SaveChanges();
     }
 }