void edit()
{
int id = Int32.Parse(datagridview2.SelectedCells[0].OwningRow.Cells["id"].Value.ToString());
hocsinh hs = db.hocsinhs.Find(id);
hs.lop = cblophs.Text;
hs.ngaysinh = dateTimePicker1.Value;
db.SaveChanges();
}
void delete()
{
try {
int idhs = Int32.Parse(txtid.Text);
hocsinh hs = db.hocsinhs.Where(p => p.id == idhs).SingleOrDefault();
db.hocsinhs.Remove(hs);
db.SaveChanges();
} catch { }
}
void addhs()
{
DateTime date = dateTimePicker1.Value;
string lophoc = cblophs.Text;
string tenhocsinh = txthocsinh.Text;
hocsinh hs = new hocsinh()
{
tenhs = tenhocsinh, lop = lophoc, ngaysinh = date
};
db.hocsinhs.Add(hs);
db.SaveChanges();
}
