private void btnThem_Click(object sender, EventArgs e) { ECHITIETHOADON ect = new ECHITIETHOADON(); ect.SOHOADON = txtshd.Text.Trim(); ect.MASP = txtmasp.Text.Trim(); int sl = 0; int.TryParse(txtsl.Text.Trim(), out sl); ect.SOLUONG = sl; float ck = 0; float.TryParse(txtck.Text.Trim(), out ck); ect.CHIETKHAU = ck; BCHITIETHOADON.Insert(ect); dgvData.DataSource = BCHITIETHOADON.SelectAll(txtshd.Text.Trim()); txttongtien.Text = tongtien() + ""; }