private void btnThem_Click_1(object sender, EventArgs e)
{
Sinhvien sv = new Sinhvien();
// tao moi tu cac thong tin trong text box
sv.manv = txtmasv.Text;
sv.hoten = txtHoten.Text;
sv.lop = txtLop.Text;
sv.diachi = txtDiachi.Text;
//goi phuong thuc Them tu class Xuly
pr.ThemSinhVien(sv);
//Them XOng thi hien thi
pr.HienThi(gridviewSinhvien);
//Goi them pthuc xoa textbox sau khi them sv
Xoatextbox();
}