private void barButtonItem2_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
        {
            string fileLocation = @"E:\";
            string fileName     = "DSTaiKhoan";

            fileLocation += fileName + ".xlsx";
            ExportFileExcel.export2FileExcel(gridView1, fileLocation);
            app obj = new app();

            obj.Visible = true;
            Workbook wb = obj.Workbooks.Open(fileLocation);
        }
        private void btnXuatExcel_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
        {
            if (cbbLopHoc.SelectedIndex < 0)
            {
                XtraMessageBox.Show("Vui lòng chọn lớp");
                return;
            }
            string fileLocation = @"E:\";
            string fileName     = "BangDiemKH" + listKhoaHoc[cbbKhoaHoc.SelectedIndex].MaKH.ToString() + "-LH" + listLopHoc[cbbLopHoc.SelectedIndex].MaLH.ToString();

            fileLocation += fileName + ".xlsx";
            ExportFileExcel.export2FileExcel(gridView1, fileLocation);
            app obj = new app();

            obj.Visible = true;
            Workbook wb = obj.Workbooks.Open(fileLocation);
        }