private void btnThem_Click(object sender, EventArgs e) { SinhVienBUL cls = new SinhVienBUL(); HocSinhPublic x = new HocSinhPublic(); x.MaSV = txtMaSV.Text; x.TenSV = txtTenSV.Text; x.MaLop = txtMaLop.Text; cls.ThemSV(x); Form1_Load(sender, e); }