protected void btnExport_Click(object sender, EventArgs e) { string maphieu = Session["maphieu"].ToString(); string macongty = Session["congty"].ToString(); DataTable dt = dal.KiemTraSoPhieuNoSize(macongty, maphieu); if (dt.Rows.Count > 0) { lblDDBH.Visible = false; txtDDBH.Visible = false; } else { lblDDBH.Visible = true; txtDDBH.Visible = true; } pnlContents.Visible = false; idButton.Visible = false; idPanelExport.Visible = true; Session["XuatFileBaoCao"] = "xuatfile"; HienThiDropBoxNhaCungUng(); }