private void btnAceptar_Click(object sender, EventArgs e)
        {
            try
            {
                validarEntidad();

                AlumnoService s = new AlumnoService();

                if (this.alumno.Id != 0)
                {
                    s.Update(alumno);
                }
                else
                {
                    s.Insert(alumno);
                }

                CommonHelper.ShowInfo("Alumno guardado con éxito.");
                this.DialogResult = DialogResult.OK;
            }
            catch (WarningException ex)
            {
                CommonHelper.ShowWarning(ex.Message);
            }
            catch (Exception ex)
            {
                CommonHelper.ShowError(ex.Message);
            }
        }