使用 iText7 C# 解析/读取 PDF 文档

Question

I'm trying to upgrade my code by using iText7 libraries. Previously I used iTextSharp libraries But looks like iText7 is totally new I tried Reading a pdf Document but facing an exception in between "Pdf Header Not Found". Here's my code

byte[] bytes = System.Convert.FromBase64String(UploadedFileByes);

MemoryStream memory = new MemoryStream(bytes);
            BinaryReader BRreader = new BinaryReader(memory);
            StringBuilder text = new StringBuilder();


            iText.Kernel.Pdf.PdfReader iTextReader = new iText.Kernel.Pdf.PdfReader(memory);
            iText.Kernel.Pdf.PdfDocument pdfDoc = new iText.Kernel.Pdf.PdfDocument(new iText.Kernel.Pdf.PdfReader(memory));



            int numberofpages = pdfDoc.GetNumberOfPages();
            for (int page = 1; page <= numberofpages; page++) {
                iText.Kernel.Pdf.Canvas.Parser.Listener.ITextExtractionStrategy strategy = new iText.Kernel.Pdf.Canvas.Parser.Listener.SimpleTextExtractionStrategy();
                string currentText = iText.Kernel.Pdf.Canvas.Parser.PdfTextExtractor.GetTextFromPage(pdfDoc.GetPage(page),strategy);
                currentText = Encoding.UTF8.GetString(ASCIIEncoding.Convert(
                    Encoding.Default, Encoding.UTF8, Encoding.Default.GetBytes(currentText)));
                text.Append(currentText);
            }

What am I doing wrong?

Answer 1

I got the solution. I used the pdfreader that i defined instead of creating new one. Here's the code. Hope it would help someone.

 byte[] bytes = System.Convert.FromBase64String(UploadedFileByes); MemoryStream memory = new MemoryStream(bytes); BinaryReader BRreader = new BinaryReader(memory); StringBuilder text = new StringBuilder(); iText.Kernel.Pdf.PdfReader iTextReader = new iText.Kernel.Pdf.PdfReader(memory); iText.Kernel.Pdf.PdfDocument pdfDoc = new iText.Kernel.Pdf.PdfDocument(iTextReader); int numberofpages = pdfDoc.GetNumberOfPages(); for (int page = 1; page <= numberofpages; page++) { iText.Kernel.Pdf.Canvas.Parser.Listener.ITextExtractionStrategy strategy = new iText.Kernel.Pdf.Canvas.Parser.Listener.SimpleTextExtractionStrategy(); string currentText = iText.Kernel.Pdf.Canvas.Parser.PdfTextExtractor.GetTextFromPage(pdfDoc.GetPage(page),strategy); currentText = Encoding.UTF8.GetString(ASCIIEncoding.Convert( Encoding.Default, Encoding.UTF8, Encoding.Default.GetBytes(currentText))); text.Append(currentText); }