使用 iTextSharp ASP.NET 替換 PDF 中的特定文本

Question

我正在嘗試使用 iTextSharp 替換 PDF 中的特定文本，但我無法替換它，我的代碼所做的只是復制與目標位置相同的文件。 誰能幫我這個。 以下是我的代碼

string src = Server.MapPath("~/Name.pdf");
    string dest = Server.MapPath("~/2.pdf");

    PdfReader reader = new PdfReader(src);
    PdfDictionary dict = reader.GetPageN(1);
    PdfObject obj = dict.GetDirectObject(PdfName.CONTENTS);

    PRStream stream = (PRStream)obj;
    byte[] data = PdfReader.GetStreamBytes(stream);
    string dd = new string(System.Text.Encoding.UTF8.GetString(data).ToCharArray());
    dd = dd.Replace("@Name", "John Smith");
    stream.SetData(System.Text.Encoding.UTF8.GetBytes(dd));

    PdfStamper stamper = new PdfStamper(reader, new System.IO.FileStream(dest, System.IO.FileMode.Create));
    stamper.Close();
    reader.Close();

Answer 1

using iTextSharp.text.pdf;
using iTextSharp.text.pdf.parser;
using System.Drawing;
using iTextSharp.text;

namespace pdf_edit_work
{
/// <summary>
/// Replace the text in PDF
/// </summary>
public class PDFEdit
{
    /// <summary>
    /// Find the text and replace in PDF
    /// </summary>
    /// <param name="sourceFile">The source PDF file where text to be searched</param>
    /// <param name="descFile">The new destination PDF file which will be saved with replaced text</param>
    /// <param name="textToBeSearched">The text to be searched in the PDF</param>
    /// <param name="textToBeReplaced">The text to be replaced with</param>
    public void ReplaceTextInPDF(string sourceFile, string descFile, string textToBeSearched, string textToBeReplaced)
    {
        ReplaceText(textToBeSearched, textToBeReplaced, descFile, sourceFile);
    }
    private void ReplaceText(string textToBeSearched, string textToAdd, string outputFilePath, string inputFilePath)
    {
        try
        {
            using (Stream inputPdfStream = new FileStream(inputFilePath, FileMode.Open, FileAccess.Read, FileShare.Read))
            using (Stream outputPdfStream = new FileStream(outputFilePath, FileMode.Create, FileAccess.Write, FileShare.ReadWrite))
            using (Stream outputPdfStream2 = new FileStream(outputFilePath, FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite))
            {
                //Opens the unmodified PDF for reading
                PdfReader reader = new PdfReader(inputPdfStream);
                //Creates a stamper to put an image on the original pdf
                PdfStamper stamper = new PdfStamper(reader, outputPdfStream); //{ FormFlattening = true, FreeTextFlattening = true };
                for (var i = 1; i <= reader.NumberOfPages; i++)
                {
                    var tt = new MyLocationTextExtractionStrategy(textToBeSearched);
                    var ex = PdfTextExtractor.GetTextFromPage(reader, i, tt); // ex will be holding the text, although we just need the rectangles [RectAndText class objects]
                    foreach (var p in tt.myPoints)
                    {
                        //Creates an image that is the size i need to hide the text i'm interested in removing
                        Bitmap transparentBitmap = new Bitmap((int)p.Rect.Width, (int)p.Rect.Height);
                        transparentBitmap.MakeTransparent();
                        iTextSharp.text.Image image = iTextSharp.text.Image.GetInstance(transparentBitmap, new BaseColor(255, 255, 255));
                        //Sets the position that the image needs to be placed (ie the location of the text to be removed)
                        image.SetAbsolutePosition(p.Rect.Left, (p.Rect.Top - 8));
                        //Adds the image to the output pdf
                        stamper.GetOverContent(i).AddImage(image, true); // i stands for the page no.

                        PdfContentByte cb = stamper.GetOverContent(i);

                        // select the font properties
                        BaseFont bf = BaseFont.CreateFont(BaseFont.HELVETICA, BaseFont.CP1252, BaseFont.NOT_EMBEDDED);
                        cb.SetColorFill(BaseColor.BLACK);
                        cb.SetFontAndSize(bf, 7);

                        // write the text in the pdf content
                        cb.BeginText();
                        // put the alignment and coordinates here
                        cb.ShowTextAligned(1, textToAdd, p.Rect.Left + 10, p.Rect.Top - 6, 0);
                        cb.EndText();
                    }
                }
                //Creates the first copy of the outputted pdf
                stamper.Close();

            }
        }
        catch (Exception ex)
        {
        }
    }
    public class RectAndText
    {
        public iTextSharp.text.Rectangle Rect;
        public String Text;
        public RectAndText(iTextSharp.text.Rectangle rect, String text)
        {
            this.Rect = rect;
            this.Text = text;
        }
    }
    public class MyLocationTextExtractionStrategy : LocationTextExtractionStrategy
    {
        //Hold each coordinate
        public List<RectAndText> myPoints = new List<RectAndText>();

        //The string that we're searching for
        public String TextToSearchFor { get; set; }

        //How to compare strings
        public System.Globalization.CompareOptions CompareOptions { get; set; }

        public MyLocationTextExtractionStrategy(String textToSearchFor, System.Globalization.CompareOptions compareOptions = System.Globalization.CompareOptions.None)
        {
            this.TextToSearchFor = textToSearchFor;
            this.CompareOptions = compareOptions;
        }

        //Automatically called for each chunk of text in the PDF
        public override void RenderText(TextRenderInfo renderInfo)
        {

            base.RenderText(renderInfo);
            //See if the current chunk contains the text
            var startPosition = System.Globalization.CultureInfo.CurrentCulture.CompareInfo.IndexOf(renderInfo.GetText(), this.TextToSearchFor, this.CompareOptions);

            //If not found bail
            if (startPosition < 0)
            {
                return;
            }

            //Grab the individual characters
            var chars = renderInfo.GetCharacterRenderInfos().Skip(startPosition).Take(this.TextToSearchFor.Length).ToList();

            //Grab the first and last character
            var firstChar = chars.First();
            var lastChar = chars.Last();


            //Get the bounding box for the chunk of text
            var bottomLeft = firstChar.GetDescentLine().GetStartPoint();
            var topRight = lastChar.GetAscentLine().GetEndPoint();

            //Create a rectangle from it
            var rect = new iTextSharp.text.Rectangle(bottomLeft[Vector.I1], bottomLeft[Vector.I2], topRight[Vector.I1], topRight[Vector.I2]);

            //Add this to our main collection
            this.myPoints.Add(new RectAndText(rect, this.TextToSearchFor));
        }

    }
}
}

---

PDFEdit 類的用法

string sourceFile = @"C:\original.pdf";
string descFile = @"C:\original_with_text_replaced.pdf";
PDFEdit pdfObj = new PDFEdit();
pdfObj.ReplaceTextInPDF(sourceFile, descFile, "text_to_be_searched", "text_to_be_replaced_with");

Answer 2

使用以下方法怎么樣：

string formFile = <Your pdf filepath goes here>;

PdfReader reader = new PdfReader(formFile);
MemoryStream stream = new MemoryStream();
PdfStamper stamper = new PdfStamper(reader, stream);
AcroFields fields = stamper.AcroFields;

fields.SetField("{{FirstName}}", objUser.FirstName);
fields.SetField("{{ContactNumber}}", objUser.EmailId);
fields.SetField("{{Address1}}", objUser.AddressLine1);
fields.SetField("{{Address2}}", objUser.AddressLine2);
fields.SetField("{{Qualification}}", objUser.Education);
fields.SetField("{{AppNumber}}", "01A2021"+objUser.UserId.ToString());

stamper.Writer.CloseStream = false;

stamper.FormFlattening = true;
stamper.Close();

stream.Position = 0;

並根據需要使用該流