iTextSharp.text.pdf.PdfCopy.AddPage C# (CSharp) Метод

        public void AddPage(PdfImportedPage iPage)
        {
            int pageNum = SetFromIPage(iPage);

            PdfDictionary thePage = reader.GetPageN(pageNum);
            PRIndirectReference origRef = reader.GetPageOrigRef(pageNum);
            reader.ReleasePage(pageNum);
            RefKey key = new RefKey(origRef);
            PdfIndirectReference pageRef;
            IndirectReferences iRef;
            indirects.TryGetValue(key, out iRef);
            if (iRef != null && !iRef.Copied) {
                pageReferences.Add(iRef.Ref);
                iRef.SetCopied();
            }
            pageRef = CurrentPage;
            if (iRef == null) {
                iRef = new IndirectReferences(pageRef);
                indirects[key] = iRef;
            }
            iRef.SetCopied();
            PdfDictionary newPage = CopyDictionary(thePage);
            root.AddPage(newPage);
            iPage.SetCopied();
            ++currentPageNumber;
        }

        /// <summary>
        /// Extract a single page from PDF file.
        /// </summary>
        /// <param name="sourceFile">The source file.</param>
        /// <param name="outputFile">The output file.</param>
        /// <param name="pageNumber">The specific page number.</param>
        public static void ExtractPage(string sourceFile, string outputFile, int pageNumber)
        {
            try
            {
                PdfReader reader = new PdfReader(sourceFile);
                if (pageNumber > reader.NumberOfPages)
                {
                    Console.WriteLine("This page number is out of reach.");
                    return;
                }

                Document document = new Document();
                PdfCopy pdfCopy = new PdfCopy(document, new FileStream(outputFile, FileMode.Create));
                document.Open();

                PdfImportedPage importedPage = pdfCopy.GetImportedPage(reader, pageNumber);
                pdfCopy.AddPage(importedPage);

                document.Close();
                reader.Close();
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }