public FileStreamResult SachBan(DateTime startDate, DateTime endDate)
        {
            List<Sach> DMSach = SachManager.getAll()
                                    .Where(s => s.tongSoLuongBanTheoThang(
                                        ((DateTime)startDate).Month,
                                        ((DateTime)startDate).Year,
                                        ((DateTime)endDate).Month,
                                        ((DateTime)endDate).Year) > 0 &&
                                        s.tongTienBanTheoThang(
                                        ((DateTime)startDate).Month,
                                        ((DateTime)startDate).Year,
                                        ((DateTime)endDate).Month,
                                        ((DateTime)endDate).Year) > 0).ToList();
            var printer = new PrintHelper();
            printer.FileName = "report.pdf";
            printer.FolderPath = "D://";
            printer.Title = "Thống kê sách bán";
            var info = new MemoryStream(printer.printSachBan(DMSach, startDate, endDate));

            return new FileStreamResult(info, "application/pdf");
        }
        private void btIn_Click(object sender, EventArgs e)
        {
            DialogResult dialogResult = MessageBox.Show("Bạn có muốn xuất tạo file báo cáo", "Thông báo", MessageBoxButtons.YesNo);
            if (dialogResult == DialogResult.Yes)
            {
                var printer = new PrintHelper();
                string x = DateTime.Now.Year + "-" + DateTime.Now.Month + "-" + DateTime.Now.Day + "-" + DateTime.Now.Hour + "-" + DateTime.Now.Minute + "-" + DateTime.Now.Second + "";

                string tenfile = x + "ReportSachBan.pdf";
                printer.FileName = tenfile;
                printer.FolderPath = "D://Report";
                printer.Title = "Báo cáo Sách bán";
                var startDate = new DateTime(_startYear, _startMonth, 1);
                var endDate = new DateTime(_endYear, _endMonth, 1);
                endDate.AddMonths(1).AddDays(-1);
                printer.printSachBan(_Sach,startDate,endDate);
                MessageBox.Show("Đã tạo file thành công , Tên file là : " + tenfile);

                //    var redListTextFont = FontFactory.RegisterDirectory(Environment.GetEnvironmentVariable("SystemRoot") + "\\fonts");
                //    var _bold = FontFactory.GetFont("Times New Roman", BaseFont.IDENTITY_H, BaseFont.EMBEDDED, 10f, iTextSharp.text.Font.BOLD, BaseColor.BLACK);
                //    var _bold1 = FontFactory.GetFont("Times New Roman", BaseFont.IDENTITY_H, BaseFont.EMBEDDED, 10f, iTextSharp.text.Font.NORMAL, BaseColor.BLACK);
                //    PdfPTable pdfTable = new PdfPTable(gdvDMSach.ColumnCount);
                //    pdfTable.DefaultCell.Padding = 3;
                //    pdfTable.WidthPercentage = 30;
                //    pdfTable.HorizontalAlignment = Element.ALIGN_CENTER;
                //    pdfTable.DefaultCell.BorderWidth = 1;
                //    pdfTable.TotalWidth = 550f;
                //    pdfTable.LockedWidth = true;
                //    float[] widths = new float[] { 70f, 120f, 120f, 120f, 120f };
                //    pdfTable.SetWidths(widths);

                //    //Adding Header row
                //    foreach (DataGridViewColumn column in gdvDMSach.Columns)
                //    {
                //        PdfPCell cell = new PdfPCell(new Phrase(column.HeaderText, _bold));
                //        cell.BackgroundColor = new iTextSharp.text.BaseColor(240, 240, 240);

                //        pdfTable.AddCell(cell);
                //    }

                //    //Adding DataRow
                //    foreach (DataGridViewRow row in gdvDMSach.Rows)
                //    {
                //        foreach (DataGridViewCell cell in row.Cells)
                //        {
                //            if (!String.IsNullOrEmpty(Convert.ToString(cell.Value)))
                //                pdfTable.AddCell(new Phrase(cell.Value.ToString(), _bold1));
                //        }
                //    }

                //    //Exporting to PDF
                //    string folderPath = @"C:\Users\huy\Desktop\Report\";
                //    string x = DateTime.Now.Year + "-" + DateTime.Now.Month + "-" + DateTime.Now.Day + "-" + DateTime.Now.Hour + "-" + DateTime.Now.Minute + "-" + DateTime.Now.Second + "";

                //    string tenfile = x + "ReportThongKeBanSach.pdf";
                //    if (!Directory.Exists(folderPath))
                //    {
                //        Directory.CreateDirectory(folderPath);
                //    }
                //    using (FileStream stream = new FileStream(folderPath + tenfile, FileMode.Create))
                //    {

                //        Document pdfDoc = new Document(PageSize.A3, 100f, 100f, 100f, 0);
                //        PdfWriter.GetInstance(pdfDoc, stream);
                //        pdfDoc.Open();
                //        var FontColour = new BaseColor(255, 0, 0);
                //        var _bold2 = FontFactory.GetFont("Times New Roman", BaseFont.IDENTITY_H, BaseFont.EMBEDDED, 20f, iTextSharp.text.Font.NORMAL, BaseColor.BLUE);
                //        Paragraph docTitle = new Paragraph("Thống kê bán sách " +"\n", _bold2);
                //        Paragraph docTitle1 = new Paragraph("Từ tháng  : " + cmbStartMonth.Text + " Năm  " + cmbStartYear.Text + "\n", _bold2);
                //        Paragraph docTitle2 = new Paragraph("đến tháng : " + cmbEndMonth.Text + " Năm  " + cmbEndYear.Text + "\n", _bold2);
                //        Paragraph docTitle3 = new Paragraph("Số lượng  : " +lbSachBanDuoc.Text+ "\n", _bold2);
                //        Paragraph docTitle4 = new Paragraph("Tổng tiền : " + lbTongTien.Text+ "\n", _bold2);
                //        docTitle.Alignment = Element.ALIGN_CENTER;
                //        docTitle1.Alignment = Element.ALIGN_LEFT;
                //        docTitle2.Alignment = Element.ALIGN_LEFT;
                //        docTitle3.Alignment = Element.ALIGN_LEFT;
                //        docTitle4.Alignment = Element.ALIGN_LEFT;

                //        pdfDoc.Add(docTitle);
                //        pdfDoc.Add(docTitle1);
                //        pdfDoc.Add(docTitle2);
                //        pdfDoc.Add(docTitle3);
                //        pdfDoc.Add(docTitle4);
                //        pdfDoc.Add(new Paragraph("\n"));
                //        pdfDoc.Add(new Paragraph("\n"));
                //        pdfDoc.Add(pdfTable);
                //        pdfDoc.Close();
                //        stream.Close();

                //        MessageBox.Show("Đã tạo file thành công , Tên file là : " + tenfile);
            }
            else if (dialogResult == DialogResult.No)
            {
                return;
            }
        }