Search for Text in PDF

// the test file
string filePdf = Server.MapPath("~/files/selectpdf.pdf");

// settings
bool caseSensitive = ChkCaseSensitive.Checked;
bool wholeWordsOnly = ChkWholeWordsOnly.Checked;

// instantiate a pdf to text converter object
PdfToText pdfToText = new PdfToText();

// load PDF file
pdfToText.Load(filePdf);

// search for text and retrieve all found text positions
TextPosition[] positions = pdfToText.Search(TxtSearchText.Text, 
    caseSensitive, wholeWordsOnly);

// open the existing PDF document in editing mode
PdfDocument doc = new PdfDocument(filePdf);

// highlight the found text in the existing PDF document
for (int i = 0; i < positions.Length; i++)
{
    TextPosition position = (TextPosition)positions[i];

    PdfPage page = doc.Pages[position.PageNumber - 1];

    PdfRectangleElement rect = new PdfRectangleElement(
        position.X, position.Y, position.Width, position.Height);
    rect.BackColor = new PdfColor(240, 240, 0);
    rect.Transparency = 30;
    page.Add(rect);
}

// save pdf document
doc.Save(Response, false, "Sample.pdf");

// close pdf document
doc.Close();

' the test file
Dim filePdf As String = Server.MapPath("~/files/selectpdf.pdf")

' settings
Dim caseSensitive As Boolean = ChkCaseSensitive.Checked
Dim wholeWordsOnly As Boolean = ChkWholeWordsOnly.Checked

' instantiate a pdf to text converter object
Dim pdfToText As New PdfToText()

' load PDF file
pdfToText.Load(filePdf)

' search for text and retrieve all found text positions
Dim positions As TextPosition() = pdfToText.Search( _
    TxtSearchText.Text, caseSensitive, wholeWordsOnly)

' open the existing PDF document in editing mode
Dim doc As New PdfDocument(filePdf)

' highlight the found text in the existing PDF document
For i As Integer = 0 To positions.Length - 1
    Dim position As TextPosition = DirectCast(positions(i), TextPosition)

    Dim page As PdfPage = doc.Pages(position.PageNumber - 1)

    Dim rect As New PdfRectangleElement( _
        position.X, position.Y, position.Width, position.Height)
    rect.BackColor = New PdfColor(240, 240, 0)
    rect.Transparency = 30
    page.Add(rect)
Next

' save pdf document
doc.Save(Response, False, "Sample.pdf")

' close pdf document
doc.Close()