private void dataGridView1_SelectionChanged(object sender, EventArgs e) { int HoadonID = int.Parse(dataGridView1.CurrentRow.Cells["HoadonbanthuocID"].Value.ToString()); int KhachhangID = int.Parse(dataGridView1.CurrentRow.Cells["KhachhangID"].Value.ToString()); Khachhang kh = APIs.GetKhachhangByID(KhachhangID); txtTenKH.Text = kh.Tenkhachhang; txtDiachi.Text = kh.Diachi; List <CTHoadonbanthuoc> lst = APIs.LstCTByHoadonID(HoadonID); listView1.Items.Clear(); float total = 0; for (int i = 0; i < lst.Count; i++) { CTHoadonbanthuoc ct = lst[i]; ListViewItem item = new ListViewItem(); item.Text = (i + 1).ToString(); Thuoc t = APIs.GetThuocByID(ct.Thuoc)[0]; item.SubItems.Add(t.Tenthuoc); item.SubItems.Add(t.Donvitinh); item.SubItems.Add(ct.Soluong.ToString()); item.SubItems.Add((ct.Dongia * 1000).ToString()); total += (float)ct.Soluong * (float)ct.Dongia * 1000; item.SubItems.Add((ct.Soluong * ct.Dongia * 1000).ToString()); listView1.Items.Add(item); } txtTotal.Text = total.ToString(); }