private void BtnCancelar_Click(object sender, EventArgs e)
        {
            FrmListadoEstudiantes newForm = FrmListadoEstudiantes.Instancia;

            newForm.Show();
            this.Close();
        }
        private void FrmEstudianteFormulario_FormClosed(object sender, FormClosedEventArgs e)
        {
            FrmListadoEstudiantes newForm = FrmListadoEstudiantes.Instancia;

            newForm.Show();
        }