private void select_grpsch(object sender, DataGridViewCellMouseEventArgs e)
{
int id = Convert.ToInt32(dataGridGrpSch.Rows[e.RowIndex].Cells[0].Value);
selectedGrpSch = db.Group_schedule.Find(id);
grp_sch_name.Text = selectedGrpSch.group_schedule_name;
sch_start.Value = selectedGrpSch.group_begin_time;
sch_end.Value = selectedGrpSch.group_end_time;
}
private void sch_add_Click(object sender, EventArgs e)
{
Group_schedule grp_sch = new Group_schedule();
grp_sch.group_schedule_name = grp_sch_name.Text;
grp_sch.group_begin_time = sch_start.Value;
grp_sch.group_end_time = sch_end.Value;
db.Group_schedule.Add(grp_sch);
db.SaveChanges();
fillDataGrpSch();
}