C# PDF Reader, Viewer Control Component
How to add, delete, update Adobe PDF text highlight without Acrobat installed in .net. Free Download

• Best PDF document reader SDK control that can highlight PDF text in Visual C# .NET framework application
• A professional annotation application able to highlight PDF file in C#.NET WinForm project without adobe reader components
• Support .NET WinForms, ASP.NET MVC in IIS, ASP.NET Ajax, Azure cloud service, DNN (DotNetNuke), SharePoint
• An ASP.NET web-server compliant library able to highlight text in PDF file online in browser such as chrome, firefox, safari, etc
• Able to remove highlighted text in PDF document in C#.NET
• Support to change PDF highlight color in Visual C# .NET class
• Able to save highlighted content to original PDF document
• Various C# source codes provides multiple ways to highlight PDF text in .NET

Users will often face the situation that you may need to emphasize the most important information from all text on a PDF page. Highlight text is such a functionality which allow users to give prominence to key words or sentences. RasterEdge XDoc.PDF SDK is a multifunctional PDF document annotation tool, which can highlight text with a simple piece of C# programming demo code.

Since RasterEdge XDoc.PDF SDK is based on .NET framework 2.0, users are enabled to use it in any type of a 32-bit or 64-bit .NET application, including ASP.NET web service and Windows Forms for any .NET Framework version from 2.0 to 4.5.

C# add highlight text annotation to pdf document

String inputFilePath = Program.RootPath + "\\" + "2.pdf";
String outputFilePath = Program.RootPath + "\\" + "Annot_3.pdf";

//  open a PDF file
PDFDocument doc = new PDFDocument(inputFilePath);
//  get the 2nd page
PDFPage page = (PDFPage)doc.GetPage(1);

//  create the annotation
PDFAnnotHighlight annot = new PDFAnnotHighlight();

annot.StartPoint = new PointF(100F, 200F);
annot.EndPoint = new PointF(300F, 400F);

//  add annotation to the page
page.AddPDFAnnot(annot);

//  save to a new file
doc.Save(outputFilePath);

C# read highlight text annotation from pdf document

String inputFilePath = Program.RootPath + "\\" + "Annot_3.pdf";

PDFDocument doc = new PDFDocument(inputFilePath);
List<IPDFAnnot> annots = PDFAnnotHandler.GetAllAnnotations(doc);
foreach (IPDFAnnot annot in annots)
{
    if (annot is PDFAnnotHighlight)
    {
        PDFAnnotHighlight obj = (PDFAnnotHighlight)annot;
        Console.WriteLine("Color: " + obj.Color.ToString());
        Console.WriteLine("Line Boundaries: ");
        foreach (RectangleF line in obj.GetLineBoundaries())
        {
            Console.WriteLine("  " + line.ToString());
        }
    }
}

C# delete all annotations from pdf document

String inputFilePath = Program.RootPath + "\\" + "1_Annots.pdf";

PDFDocument doc = new PDFDocument(inputFilePath);
//  get all annotations in the 1st page
PDFPage page = (PDFPage)doc.GetPage(0);
List<IPDFAnnot> annots = PDFAnnotHandler.GetAllAnnotations(page);
//  remove all annotations in the 1st page
PDFAnnotHandler.DeleteAnnotation(doc, annots);