使用 PDFSharp 在 PDF 中查找单词

Question

I am using PDFSharp. I need help. I need to check wether the document contains the word "abc". Example:

11abcee  = true 
444abcggw = true
778ab = false

I wrote this code, but it does not work as expected:

    PdfDocument document = PdfReader.Open("c:\\abc.pdf");
    PdfDictionary dictionary = new PdfDictionary(document);

    string a = dictionary.Elements.GetString("MTZ");

    if (a.Equals("MTZ"))
    {
        MessageBox.Show("OK", "");
    }
    else 
    {
        MessageBox.Show("NO", "");
    }

Am I missing something?

Answer 1

maybe this SO entry will help you: PDFSharp alter Text repositioning . It links to here - text extraction example with PDFSharp.

Answer 2

Old question, but here is an example.

Note: c# 7.0+ is required to use IS new local variable assignment.

Note: This example uses PDFSharp installed from Package Manager. "Install-Package PdfSharp -Version 1.50.5147"

Note: For my requirements, I only needed to search the first page of my PDFs, update if needed.

using (PdfDocument inputDocument = PdfReader.Open(filePath, PdfDocumentOpenMode.Import))
{
    if (searchPDFPage(ContentReader.ReadContent(inputDocument.Pages[0]), searchText))
    {
        // match found.
    }
}

This code looks for a cString that starts with a pound sign, the OP would need to use a Contains string function.

private bool searchPDFPage(CObject cObject, string searchText)
    {
        if (cObject is COperator cOperator)
        {
            if (cOperator.OpCode.Name == OpCodeName.Tj.ToString() ||
                cOperator.OpCode.Name == OpCodeName.TJ.ToString())
            {
                foreach (var cOperand in cOperator.Operands)
                {
                    if (searchPDFPage(cOperand, searchText))
                    {
                        return true;
                    }
                }
            }
        }
        else if (cObject is CSequence cSequence)
        {
            foreach (var element in cSequence)
            {
                if (searchPDFPage(element, searchText))
                {
                    return true;
                }
            }
        }
        else if (cObject is CString cString)
        {
            if (cString.Value.StartsWith("#"))
            {
                if (cString.Value.Substring(2) == searchText)
                {
                    return true;
                }
            }
        }
        return false;
    }

Credit: This example was modified based on this answer: C# Extract text from PDF using PdfSharp