Read Write in Existing Pdf File in C# using iTextSharp.

How we read and write pdf file data using Itextsharp.Like



public string ReadPdfFile(string fileName)
{
    StringBuilder text = new StringBuilder();

    if (File.Exists(fileName))
    {


        PdfReader pdfReader = new PdfReader(fileName);

        for (int page = 1; page <= pdfReader.NumberOfPages; page++)
        {
            ITextExtractionStrategy strategy = new SimpleTextExtractionStrategy();
            string currentText = PdfTextExtractor.GetTextFromPage(pdfReader, page, strategy);

            currentText = Encoding.UTF8.GetString(ASCIIEncoding.Convert(Encoding.Default, Encoding.UTF8, Encoding.Default.GetBytes(currentText)));
            text.Append(currentText);
        }
        pdfReader.Close();
    }
    return text.ToString();
}


Edit a PDF Document from an existing PDF Document using Itextsharp:

string originalFile = "Original.pdf";
string copyOfOriginal = "CopyFile.pdf";
using (FileStream fs = new FileStream(originalFile, FileMode.Create, FileAccess.Write, FileShare.None))
using (Document doc = new Document(PageSize.LETTER))
using (PdfWriter writer = PdfWriter.GetInstance(doc, fs))
{
    doc.Open();
    doc.Add(new Paragraph("Hi! I'm Original"));
    doc.Close();
}
PdfReader reader = new PdfReader(originalFile);
using (FileStream fs = new FileStream(copyOfOriginal, FileMode.Create, FileAccess.Write, FileShare.None))
// Creating iTextSharp.text.pdf.PdfStamper object to write
// Data from iTextSharp.text.pdf.PdfReader object to FileStream object
using (PdfStamper stamper = new PdfStamper(reader, fs)) { }