private void btnEliminar_Click(object sender, EventArgs e)
        {
            AlquilerDAO rec = new AlquilerDAO();

            rec.BorrarAlquiler(a);
            rec.Select("todo", dataGridView1);
            btnActualizar.Enabled = false;
            btnEliminar.Enabled   = false;
        }
        private void button1_Click(object sender, EventArgs e)
        {
            AlquilerDAO alq = new AlquilerDAO();

            alq.Select(txtConsulta.Text, dataGridView1);
        }