private void Alumnos_Grid_CellBeginEdit(object sender, DataGridViewCellCancelEventArgs e)
        {
            if (this is FormularioNotasPracticasViewForm)
            {
                return;
            }

            if (Alumnos_Grid.Columns[e.ColumnIndex].Name == Recuparada.Name)
            {
                DataGridViewRow row  = Alumnos_Grid.CurrentRow;
                Alumno_Practica item = row.DataBoundItem as Alumno_Practica;
                if (item.Calificacion == Resources.Labels.APTO_LABEL ||
                    item.Calificacion == Resources.Labels.SIN_CALIFICAR_LABEL)
                {
                    e.Cancel = true;
                }
                Alumnos_Grid.Refresh();
            }
            if (Alumnos_Grid.Columns[e.ColumnIndex].Name == FechaRecuperacion.Name)
            {
                DataGridViewRow row  = Alumnos_Grid.CurrentRow;
                Alumno_Practica item = row.DataBoundItem as Alumno_Practica;
                if (!item.Recuperada)
                {
                    e.Cancel = true;
                }
                Alumnos_Grid.Refresh();
            }
        }
        private void Alumnos_Grid_CellClick(object sender, DataGridViewCellEventArgs e)
        {
            if (this is FormularioNotasPracticasViewForm)
            {
                return;
            }

            if (Alumnos_Grid.CurrentRow == null)
            {
                return;
            }
            if (e.ColumnIndex == -1 || e.RowIndex == -1)
            {
                return;
            }

            if (Alumnos_Grid.Columns[e.ColumnIndex].Name == Calificacion.Name)
            {
                DataGridViewRow row  = Alumnos_Grid.CurrentRow;
                Alumno_Practica item = row.DataBoundItem as Alumno_Practica;
                ModificaNotaPracticasAction(item);
                Alumnos_Grid.Refresh();
            }
        }