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Danilo
Asked: 2021-12-23 13:05:44 +0800 CST 2021-12-23 13:05:44 +0800 CST

How to join two pdf documents that are generated with itextsharp? in C#

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Good day. I am trying to join two pdf documents that I am generating, since each document must have a different footer. For example I want to create a copy of the other with a different footer on its pages. I have the following code:

public ActionResult genera_report_factura(string empresa, string registros)
    {
        string Path = Server.MapPath("~/Upload/");
        string error = "";
        try
        {
            byte[] pdf = null;
            using (MemoryStream stream = new System.IO.MemoryStream())
            {
                int h_inferior = 200;
                using (var pdfDoc = new Document(PageSize.LETTER, 25, 25, 235, h_inferior))
                {
                    var pdfWriter = PdfWriter.GetInstance(pdfDoc, stream);
                    pdfWriter.PageEvent = new HeaderFooter();
                    pdfDoc.Open();
                    PdfPTable table = new PdfPTable(3);
                    table.DefaultCell.Border = Rectangle.NO_BORDER;
                    table.WidthPercentage = 100;
                    table.HorizontalAlignment = 1;
                    float[] widths = new float[] { 20, 50, 30 };
                    table.SetWidths(widths);
                    Paragraph celda = new Paragraph();

                    PdfPCell cell = new PdfPCell();
                    celda = new Paragraph();
                    celda.Add(new Chunk("PRIMER DOCUMENTO", FontFactory.GetFont("Arial", 9, Font.BOLD, BaseColor.BLACK)));
                    celda.Alignment = Element.ALIGN_LEFT;
                    cell = new PdfPCell();
                    cell.Colspan = 3;
                    cell.Border = 0;
                    cell.AddElement(celda);
                    table.AddCell(cell);
                    pdfDoc.Add(table);
                    pdfDoc.Close();

                }
                using (var pdfDoc2 = new Document(PageSize.LETTER, 25, 25, solo_fatura, h_inferior + h_cedible))
                {
                    var pdfWriter2 = PdfWriter.GetInstance(pdfDoc2, stream);
                    pdfWriter.PageEvent = new EVENTOHEADERDOS();

                    pdfDoc2.Open();//Referencia a objeto no establecida como instancia de un objeto
                    PdfPTable table2 = new PdfPTable(3);
                    table2.DefaultCell.Border = Rectangle.NO_BORDER;
                    table2.WidthPercentage = 100;
                    table2.HorizontalAlignment = 1;
                    float[] widths2 = new float[] { 20, 50, 30 };
                    table2.SetWidths(widths2);
                    Paragraph celda2 = new Paragraph();

                    PdfPCell cell2 = new PdfPCell();
                    celda2 = new Paragraph();
                    celda2.Add(new Chunk("SEGUNDO documento", FontFactory.GetFont("Arial", 9, Font.BOLD, BaseColor.BLACK)));
                    celda2.Alignment = Element.ALIGN_LEFT;
                    cell2 = new PdfPCell();
                    cell2.Colspan = 3;
                    cell2.Border = 0;
                    cell2.AddElement(celda2);
                    table2.AddCell(cell2);
                    pdfDoc2.Add(table2);
                    pdfDoc2.Close();

                }
                pdf = stream.ToArray();
            }
           
            return File(pdf, "application/pdf");
        }
        catch (Exception ex)
        {
            error = ex.Message;
            System.IO.File.WriteAllText(Path + "wow_error.txt": " + error);
            return null;
        }
    }

But I get the following error:

Object reference not set as an instance of an object and right on the line where I have defined :pdfDoc2.Open();

I tried this other way, I don't get an error, but the pdfDoc2 doesn't write or generate anything:

public ActionResult genera_report_factura(string empresa, string registros)
    {
        string Path = Server.MapPath("~/Upload/");
        string error = "";
        try
        {
            byte[] pdf = null;
            using (MemoryStream stream = new System.IO.MemoryStream())
            {
                int h_inferior = 200;
                using (var pdfDoc = new Document(PageSize.LETTER, 25, 25, 235, h_inferior))
                {

                    var pdfWriter = PdfWriter.GetInstance(pdfDoc, stream);
                    pdfWriter.PageEvent = new HeaderFooter();
                    pdfDoc.Open();
                    PdfPTable table = new PdfPTable(3);
                    table.DefaultCell.Border = Rectangle.NO_BORDER;
                    table.WidthPercentage = 100;
                    table.HorizontalAlignment = 1;
                    float[] widths = new float[] { 20, 50, 30 };
                    table.SetWidths(widths);
                    Paragraph celda = new Paragraph();

                    PdfPCell cell = new PdfPCell();
                    celda = new Paragraph();
                    celda.Add(new Chunk("PRIMER DOCUMENTO", FontFactory.GetFont("Arial", 9, Font.BOLD, BaseColor.BLACK)));
                    celda.Alignment = Element.ALIGN_LEFT;
                    cell = new PdfPCell();
                    cell.Colspan = 3;
                    cell.Border = 0;
                    cell.AddElement(celda);
                    table.AddCell(cell);
                    pdfDoc.Add(table);
                    
                    
                    var pdfDoc2 = new Document(PageSize.LETTER, 25, 25, solo_fatura, h_inferior);
                

                    var pdfWriter2 = PdfWriter.GetInstance(pdfDoc2, stream);
                    pdfWriter.PageEvent = new EVENTOHEADERDOS();

                    pdfDoc2.Open();
                    PdfPTable table2 = new PdfPTable(3);
                    table2.DefaultCell.Border = Rectangle.NO_BORDER;
                    table2.WidthPercentage = 100;
                    //table.SpacingBefore = 605f;

                    //0=Left, 1=Centre, 2=Right
                    table2.HorizontalAlignment = 1;
                    float[] widths2 = new float[] { 20, 50, 30 };
                    table2.SetWidths(widths2);
                    Paragraph celda2 = new Paragraph();

                    PdfPCell cell2 = new PdfPCell();
                    celda2 = new Paragraph();
                    celda2.Add(new Chunk("SEGUNDO documento", FontFactory.GetFont("Arial", 9, Font.BOLD, BaseColor.BLACK)));
                    celda2.Alignment = Element.ALIGN_LEFT;
                    cell2 = new PdfPCell();
                    cell2.Colspan = 3;
                    cell2.Border = 0;
                    cell2.AddElement(celda2);
                    table2.AddCell(cell2);
                    pdfDoc2.Add(table2);
                    
                    
                    pdfDoc.Close();
                    //pdfDoc2.Close();//si lo coloco se cae, porque me dice que no se puede cerrar un bloque que ya está cerrado


                }
                

                
                pdf = stream.ToArray();

            }
           
            return File(pdf, "application/pdf");
        }
        catch (Exception ex)
        {

            error = ex.Message;
            System.IO.File.WriteAllText(Path + "wow_error.txt", linea + ": " + error);
            return null;
        }

    }

If anyone has any ideas, I would greatly appreciate it or an example. Best regards.

c#

1 Answers

  1. Best Answer

    I already solved it, for those who need a solution, here is a contribution:

    public ActionResult genera_report_factura(string empresa, string registros)
    {
        byte[] mergedPdf = null;

        List<byte[]> pdf = new List<byte[]>();

        pdf.Add(crear_y_guarda_pdf_factura(empresa, registros, 0));
        pdf.Add(crear_y_guarda_pdf_factura(empresa, registros, 1));


        using (MemoryStream ms = new MemoryStream())
        {
            using (Document document = new Document())
            {
                using (PdfCopy copy = new PdfCopy(document, ms))
                {
                    document.Open();

                    for (int i = 0; i < pdf.Count; ++i)
                    {
                        PdfReader reader = new PdfReader(pdf[i]);
                        // loop over the pages in that document
                        int n = reader.NumberOfPages;
                        for (int page = 0; page < n;)
                        {
                            copy.AddPage(copy.GetImportedPage(reader, ++page));
                        }
                    }
                    document.Close();
                }
            }
            mergedPdf = ms.ToArray();
       

        return File(mergedPdf, "application/pdf");

    }

    The idea is to create the pdf with itexsharp separately, return a byte[] and in the function that calls them, store it in a list to join them.

    Greetings, I hope the example will serve you

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