- Add Long Term Validation (LTV) data to an existing signature
- How to downscale all images in a PDF
- How to generate and export certificates
- How to downscale all images in a PDF
- Add Stamp to PDF
- How to reduce PDF file size
- Highlight fields in PDF
- Add a note to PDF
- Resize PDF pages
- Extract glyph boxes from PDF
- Use TrueType font collections
- Layout text with MultilineTextShape
- Merge PDF files in C# .NET
- How do I extract page destinations from bookmarks?
- Clip PDF page content in C#
- Fill PDF form
- Extract glyphs and sort by reading order
- Add bookmarks to PDF
- How to scale content of PDF
- Create rectangles with rounded corners
- Create text with decorations
- TIFF to PDF C#
- Crop content on a PDF page
- How to embed files in a PDF document
- Remove graphics from PDF
- Change the color inside a PDF
- Import FDF into PDF
- Flatten PDF form
- Digitally sign a PDF form in C# or VB.NET
- Vector graphics in PDF
- Translate PDF page content
- Extract graphics from PDF
- Determine the content bounding box
- Search text in PDF
- Convert PDF to plain text
- Flatten Markup Annotation
- Add text field to PDF
- Extract embedded files from PDF
- Extract images from PDF
- Add a Diagonal Watermark to PDF in C#
- Fit image to PDF page
- Add simple html text to PDF
- Add multiline text to a PDF document
- Add single-line text to PDF
- Create a new digitally signed PDF document
- PDF Viewer Preferences
- Change page orientation PDF
- Split PDF pages in C# and VB.NET
- Append two or more existing PDF files
- Determine if a PDF only contains images
- Add footer to PDF
- Convert SVG to PDF
- Add hyperlink to PDF
- Rotate a PDF page
- Change the formatting of a numeric field
- How to mirror PDF pages and other shapes
- Fill in a template PDF document
- How to add autosized text to PDF
- Create formfields in PDF documents
- Export FDF from PDF form
- Add a link with an internal destination to PDF
- Remove PDF security settings
- Add a link to PDF with an external destination
- How to sign and verify updates to a PDF document
- Embed TrueType font
- How to create a tiling for shapes in PDF
- EMF to PDF as vector image
- Replace field with image
- Add a rubber stamp annotation with a custom icon
- Create a text annotation in PDF with rich text
- Read and write meta data from PDF
- Create a custom signature handler to sign and verify PDF documents
- Download and convert image to PDF
- Add barcodes to PDF
- Tagged PDF
- PDFKit.NET 5.0 - detailed changes to the API
- Create tagged PDF
- PDFKit.NET 5.0 and .NET Core
- PDFKit.NET 5.0 and Xamarin
- Dynamic XFA
- PDFKit.NET 5.0 .NET Standard API
- .NET Core console app on MacOS
- Add tags to existing PDF
- Read PDF tags
- Merge XDP data with dynamic XFA form
- Fill XFA form and export XDP data
- Fill and save dynamic XFA form
- Use PDFKit.NET 5.0 with a Xamarin.Forms app
- Use multiple licenses
- Licensing and .NET Standard
- Reduce PDF size
- Disable submit button after submitting
- Write Document to HttpResponse
Search text in PDF
This article shows how to search a PDF for text in C# using the Document. Find method and the TextFindCriteria and TextMatchEnumerator classes.
This code sample visualizes the results by saving a copy of the searched document with all matches highlighted and marked with the match position (first match, second match, etc.).
Resulting PDF page
This is what the result of the below code sample looks like:
C# code sample – search text in PDF
It is possible to search text on a specific page by calling Page.Find or in the entire PDF document by calling Document.Find. The signature of both methods is the same. The search criteria are defined by passing a TextFindCriteria instance. The results are returned as a TextMatchEnumerator instance. This code sample demonstrates Document.Find but everything applies to Page.Find as well.
// open PackingLightBrochure.
using ( FileStream fileIn = new FileStream( @"..\..\..\inputDocuments\PackingLightBrochure.pdf", FileMode.Open, FileAccess.Read ) )
{
//create document
Document document = new Document( fileIn );
//criteria for searching "PDF", it does not have to match a whole word and the case also does not have to match
TextFindCriteria criteria = new TextFindCriteria( "PDF", false, false );
//get a list of search results
TextMatchEnumerator enumerator = document.Find( criteria );
int resultIndex = 0;
foreach( TextMatch match in enumerator )
{
GlyphCollection glyphs = match.Glyphs;
Glyph firstGlyph = glyphs[0];
Glyph lastGlyph = glyphs[glyphs.Count - 1];
//create a rectangle over the found text.
RectangleShape rect = new RectangleShape(
firstGlyph.BottomLeft.X,
firstGlyph.BottomLeft.Y,
lastGlyph.TopRight.X - firstGlyph.BottomLeft.X,
lastGlyph.TopRight.Y - firstGlyph.BottomLeft.Y );
rect.Brush = new SolidBrush( System.Drawing.Color.Yellow );
rect.Pen = null; //the rectangle has no outline
rect.Opacity = 128;
//coordinates are in Overlay space, not VisualOverlay space.
match.Page.Overlay.Add(rect);
//now we create a textshape to print the result index onto.
MultilineTextShape textShape = new MultilineTextShape();
TranslateTransform translate = new TranslateTransform( firstGlyph.BottomLeft.X, firstGlyph.BottomLeft.Y );
textShape.Transform = translate;
textShape.Width = lastGlyph.TopRight.X - firstGlyph.BottomLeft.X;
textShape.Height = lastGlyph.TopRight.Y - firstGlyph.BottomLeft.Y;
translate.Y += textShape.Height; //correct different origin.
textShape.HorizontalAlignment = HorizontalAlignment.Center;
textShape.Opacity = 200;
Fragment fragment = new Fragment((++resultIndex).ToString(), 0); //0 means autosized.
fragment.TextColor = RgbColor.Red;
textShape.Fragments.Add( fragment );
//add the text to the page and print it over the yellow rectangle
match.Page.Overlay.Add( textShape );
}
//write the new PDF document
using ( FileStream fileOut = new FileStream( @"..\..\searchtext.pdf", FileMode.Create, FileAccess.Write ) )
{
document.Write( fileOut );
}
}
' open PackingLightBrochure.
Using fileIn As New FileStream("..\..\..\inputDocuments\PackingLightBrochure.pdf", FileMode.Open, FileAccess.Read)
'create document
Dim document As New Document(fileIn)
Dim criteria As New TextFindCriteria("PDF", False, False)
'criteria.Backwards = true;
Dim enumerator As TextMatchEnumerator = document.Find(criteria)
Dim order As Integer = 0
For Each match As TextMatch In enumerator
Console.WriteLine("Match found at page: " & match.Page.Index)
Dim glyphs As GlyphCollection = match.Glyphs
Dim firstGlyph As Glyph = glyphs(0)
Dim lastGlyph As Glyph = glyphs(glyphs.Count - 1)
'create a rectangle over the found text.
Dim rect As New RectangleShape(firstGlyph.BottomLeft.X, firstGlyph.BottomLeft.Y, lastGlyph.TopRight.X - firstGlyph.BottomLeft.X, lastGlyph.TopRight.Y - firstGlyph.BottomLeft.Y)
rect.Brush = New SolidBrush(System.Drawing.Color.Yellow)
rect.Pen = Nothing
rect.Opacity = 128
'coordinated are in Overlay space, not VisualOverlay space.
match.Page.Overlay.Add(rect)
'print the order.
Dim textShape As New MultilineTextShape()
Dim translate As New TranslateTransform(firstGlyph.BottomLeft.X, firstGlyph.BottomLeft.Y)
textShape.Transform = translate
textShape.Width = lastGlyph.TopRight.X - firstGlyph.BottomLeft.X
textShape.Height = lastGlyph.TopRight.Y - firstGlyph.BottomLeft.Y
translate.Y += textShape.Height
'correct different origin.
textShape.HorizontalAlignment = HorizontalAlignment.Center
textShape.Opacity = 200
Dim fragment As New Fragment((System.Threading.Interlocked.Increment(order)).ToString(), 0)
'autosized.
fragment.TextColor = TallComponents.PDF.Colors.RgbColor.Red
textShape.Fragments.Add(fragment)
match.Page.Overlay.Add(textShape)
Next
Using fileOut As New FileStream("..\..\searchtext.pdf", FileMode.Create, FileAccess.Write)
document.Write(fileOut)
End Using
End Using

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