Converting Comments of a RadFlowDocument to Annotations in RadFixedDocument

Updated on Jun 5, 2026

Environment

Version	Product	Author
2025.3.806	RadWordsProcessing	Desislava Yordanova

Description

This article demonstrates how to extract comments from Word (DOCX) documents and add them as annotations to the converted PDF document. Currently, the conversion to PDF does not preserve comments from Word documents.

This knowledge base article also answers the following questions:

• How to extract comments from Word documents using RadWordsProcessing?

• How to convert a DOCX file to PDF format?

• How to convert Word document comments to PDF annotations?

  

Solution

To achieve the desired behavior, follow these steps:

1. Import the existing DOCX file to RadFlowDocument.

2. Convert the RadFlowDocument to PDF format (RadFixedDocument).

3. Extract the Comments from the RadFlowDocument and programmatically add Annotations to the RadFixedDocument.

4. Export the RadFixedDocument to a PDF file.

csharp

        static void Main(string[] args)
        {
            RadFlowDocument flowDocument;
            using (Stream input = File.OpenRead("Test.docx"))
            {
                //or DocFormatProvider for .doc files
                var docxProvider = new DocxFormatProvider();
                flowDocument = docxProvider.Import(input, TimeSpan.FromSeconds(10));
            }

            // Convert RadFlowDocument to RadFixedDocument for PDF export
            var flowToPdfProvider = new Telerik.Windows.Documents.Flow.FormatProviders.Pdf.PdfFormatProvider();
            RadFixedDocument fixedDocument;

            using (var memoryStream = new MemoryStream())
            {
                flowToPdfProvider.Export(flowDocument, memoryStream, TimeSpan.FromSeconds(10));
                memoryStream.Position = 0;

                var fixedPdfProvider = new Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.PdfFormatProvider();
                fixedDocument = fixedPdfProvider.Import(memoryStream, TimeSpan.FromSeconds(10));
            }

            // Add annotations for each comment
            AddCommentsAsAnnotations(fixedDocument, flowDocument);

            string outputFilePath = "output.pdf";
            // Export the final PDF with annotations
            using (Stream output = File.Create(outputFilePath))
            {
                var pdfProvider = new Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.PdfFormatProvider();
                pdfProvider.Export(fixedDocument, output, TimeSpan.FromSeconds(10));
            }

            Process.Start(new ProcessStartInfo() { FileName = outputFilePath, UseShellExecute = true });
        }

        private static void AddCommentsAsAnnotations(RadFixedDocument fixedDocument, RadFlowDocument flowDocument)
        {
            // This is a simplified approach - in a real scenario, you'd need to map comment positions
            // from the flow document to the fixed document coordinates

            int commentIndex = 0;
            foreach (Comment comment in flowDocument.Comments)
            {

                var start = comment.CommentRangeStart;
                var end = comment.CommentRangeEnd;
                var paragraph = start.Paragraph;
                System.Text.StringBuilder commentTextBuilder = new System.Text.StringBuilder();
                foreach (Paragraph commentBlock in comment.Blocks)
                {
                    foreach (Run inline in commentBlock.Inlines)
                    {
                        commentTextBuilder.AppendLine(inline.Text);
                    }
                }
                string commentText = commentTextBuilder.ToString();
                // Get all inlines between start and end
                var inlines = paragraph.Inlines
                    .SkipWhile(inline => inline != start)
                    .Skip(1)
                    .TakeWhile(inline => inline != end);

                var associatedText = string.Join("", inlines
                    .OfType<Run>()
                    .Select(run => run.Text));

                Debug.WriteLine($"Comment: {commentText}");
                Debug.WriteLine($"Associated Text: {associatedText}");

                if (fixedDocument.Pages.Count > 0)
                {
                    TextSearch search = new TextSearch(fixedDocument);
                    SearchResult result = search.Find(associatedText, TextSearchOptions.Default);
                    if (result.Result != null)
                    {
                        System.Windows.Rect rect = result.GetWordBoundingRect();
                        RadFixedPage page = result.GetResultPage();
                        TextAnnotation annotation = page.Annotations.AddText(rect);
                        annotation.Contents = commentTextBuilder.ToString();
                        annotation.Opacity = 0.5;
                        annotation.Color = new RgbColor(255, 0, 0);  
                    }
                }
            }

See Also

• RadFlowDocument
• RadFixedDocument