private void cmbloaikh1_SelectedIndexChanged(object sender, EventArgs e) { if (ck == 0) { txtthongkeloaikh.Text = tkBLL.Thongke_theoLoaiKH(int.Parse(cmbloaikh1.SelectedValue.ToString())).ToString(); tkBLL.Hienthi_TKLoaiKH(lvthongkeloaikh, int.Parse(cmbloaikh1.SelectedValue.ToString())); } if (ck == 1) { txtthongkeloaikh.Text = tkBLL.Thongke_theoLoaiKH(1).ToString(); tkBLL.Hienthi_TKLoaiKH(lvthongkeloaikh, 1); } }