UtilitatPdf/UtilitatPdf/PdfMergeFiles.cs

using System;
using System.Collections.ObjectModel;
using System.IO;
using iText.Kernel.Pdf;
using iText.Kernel.Utils;

namespace UtilitatPdf
{
    public class PdfMergeFiles
    {
        private PdfDocument _pdfDocument = null;
        private PdfDocument _pdfDocument2 = null;
        private PdfMerger _pdfMerger = null;

        private static string tmpFolder = System.IO.Path.GetTempPath();
        private string _oldtmpFile = string.Empty;
        private string _tmpFile = string.Empty;
        private string _tmpFile2 = string.Empty;
        private bool _mergeOK = false;
        private string _FinalPdfFile = string.Empty;

        public PdfMergeFiles(string FinalPdfFile, bool DeleteIfExists = true)
        {
            if (string.IsNullOrEmpty(FinalPdfFile))
            {
                throw new Exception();
            }
            else
            {
                _FinalPdfFile = FinalPdfFile;
                if (DeleteIfExists)
                {
                    if (new FileInfo(_FinalPdfFile).Exists) File.Delete(_FinalPdfFile);
                }
            }
        }
        public bool AddFiles(ObservableCollection<PdfInfo> sourceFiles)
        {
            foreach (PdfInfo fitxer in sourceFiles)
            {
                if (!this.AddFile(fitxer.FileName))
                {
                    return false;
                }
            }
            return true;
        }
        public bool AddFile(string PdfFilename)
        {
            checkVars(PdfFilename);

            if (_mergeOK)
            {
                Random numr = new Random();
                _oldtmpFile = tmpFolder + numr.Next(1, 99999).ToString() + "tmpfile.pdf";

                try
                {
                    _pdfDocument = new PdfDocument(new PdfReader(_tmpFile), new PdfWriter(_oldtmpFile), new StampingProperties().UseAppendMode());

                    _pdfDocument2 = new PdfDocument(new PdfReader(_tmpFile2));

                    _pdfMerger = new PdfMerger(_pdfDocument);
                    _pdfMerger.Merge(_pdfDocument2, 1, _pdfDocument2.GetNumberOfPages());

                    this.ClosePdfDocs();
                }
                catch (IOException)
                {
                    throw new IOException();
                }
                catch(Exception)
                {
                    throw new Exception();
                }
                finally
                {
                    _tmpFile = _oldtmpFile;
                    _tmpFile2 = string.Empty;
                    _oldtmpFile = string.Empty;
                    _mergeOK = false;
                }
            }
            return true;
        }
        public void Generate()
        {
            File.Copy(_tmpFile, _FinalPdfFile);
        }
        private void ClosePdfDocs()
        {
            _pdfDocument?.Close();
            _pdfDocument2?.Close();
            _pdfMerger?.Close();
        }
        private void checkVars(string file)
        {
            if (string.IsNullOrEmpty(_tmpFile))
            {
                _tmpFile = file;
            }
            else
            {
                _tmpFile2 = file;
            }
            
            if (!string.IsNullOrEmpty(_tmpFile) && !string.IsNullOrEmpty(_tmpFile2)) _mergeOK = true;
        }

    }
}