A bookmark marks a specific location in a document for referencing and assigns a name to that location so that the user can easily navigate to that particular location. GcWord provides you Bookmark class which represents a bookmark range in the content. Using GcWord, you can add bookmarks in a document with Add method of the BookmarkCollection class and delete them using Delete method of the Bookmark class.

Add Bookmark

To add a bookmark:

1. Define a bookmark.

2. Add a paragraph to be marked by a bookmark.

3. Apply bookmark to the paragraph by adding a bookmark to the bookmark collection using Add method of the BookmarkCollection class.

4. Add a hyperlink that navigates to the bookmark location on clicking, using the Add method of the HyperlinkCollection class.

   var section = doc.Body.Sections.First;
   
   // Add the first paragraph          
   var p = section.GetRange().Paragraphs.Add("A bookmark marks a specific location" +
       " in a document for referencing and assigns a name to that location so that" +
       " the user can easily navigate to that particular location.");
   
   //Add a paragraph to the section
   for (var pr = 1; pr <= 30; pr++)
   {
       section.GetRange().Paragraphs.Add("Section1: Test Paragraph");
   }
   
   //Define bookmark name
   var bmk = "Bookmark1";
   
   // Add a paragraph
   var pb = section.GetRange().Paragraphs.Add($"{bmk} points here.");
   
   //Mark the paragraph with a bookmark
   pb.GetRange().Bookmarks.Add(bmk);
   
   //Create hyperlink text to jump to the bookmark location(paragraph)
   p.GetRange().Runs.Add("Jump to");
   p.GetRange().Hyperlinks.Add(bmk, $"{bmk}");
   p.GetRange().Runs.Add("at the end of the document.");
   
   //Save the document
   doc.Save("AddBookmark.docx");

Modify Bookmark

To modify a bookmark:

1. Access a bookmark to modify from the bookmarks collection using Bookmarks property of the RangeBase class. For example, access the first bookmark.

2. Modify the bookmark name using Name property of the Bookmark class.

3. Update the bookmark name in the hyperlink created for the bookmark.

   doc.Load("AddBookmark.docx");
   
   //Modify the bookamrk name
   var newBmk = "TestBookmark";
   Bookmark bmark = 
      doc.Body.Sections.First.GetRange().Paragraphs.Last.GetRange().Bookmarks.First;
   bmark.Name = newBmk;
   
   //Update the bookmark name in the hyperlink created for the bookmark
   Hyperlink hyperlink_bookmark = 
      doc.Body.Sections.First.GetRange().Paragraphs.First.GetRange().Hyperlinks.First;
   hyperlink_bookmark.Anchor = newBmk;
   hyperlink_bookmark.GetRange().Texts[0].Value = newBmk;
   
   //Save the document
   doc.Save("ModifyBookmark.docx");

Delete Bookmark

To delete a bookmark, access the bookmark from the bookmark collection using Bookmarks property of the RangeBase class and delete it using the Delete method.

//Load the existing word document in GcWord instance
doc.Load("AddBookmark.docx");

//Delete bookmark
Bookmark bmark = 
   doc.Body.Sections.First.GetRange().Paragraphs.Last.GetRange().Bookmarks.First;
bmark.Delete();

//Delete hyperlink to bookmark
doc.Body.Sections.First.GetRange().Paragraphs.First.GetRange().Runs[1].Delete();
doc.Body.Sections.First.GetRange().Paragraphs.First.GetRange().Hyperlinks.First.Delete();
doc.Body.Sections.First.GetRange().Paragraphs.First.GetRange().Runs.Last.Delete();

//Save the document
doc.Save("DeleteBookmark.docx");

For more information on how to implement bookmarks using GcWord, see GcWord sample browser.