Inserting page number in place of a placeholder(keeping html formatting intact)

I am converting an html string to word document with the help of Aspose. I have a piece of string for the header which is something like "
Page Number: @[PageNumber]@**Any Text**". Now, I have to insert the current page number of the document in place of the placeholder ‘@[PageNumber]@’. Please guide me on how to do it. I need to keep the formatting of the html intact.

Hi Vivek,

Thanks for your inquiry. You can achieve your requirement by implementing IReplacingCallback interface. Please use the same approach shared at following documentation link to find text and insert page field.

Please read the following article about ‘Find and Replace’ and check the following code example for your kind reference. Hope this helps you.

Please let us know if you have any more queries.

Document doc = new Document();
DocumentBuilder builder = new DocumentBuilder(doc);
builder.InsertHtml("Header Page Number: @[PageNumber]@<b>Any Text</b>");
doc.Range.Replace(new Regex("@\\[PageNumber\\]@"), new ReplaceEvaluatorInsertPage(), false);
doc.Save(MyDir + "Out.docx");
private class ReplaceEvaluatorInsertPage: IReplacingCallback
    /// This method is called by the Aspose.Words find and replace engine for each match.
    /// This method highlights the match string, even if it spans multiple runs.
    ReplaceAction IReplacingCallback.Replacing(ReplacingArgs e)
        // This is a Run node that contains either the beginning or the complete match.
        Node currentNode = e.MatchNode;
        // The first (and may be the only) run can contain text before the match,
        // in this case it is necessary to split the run.
        if (e.MatchOffset> 0)
            currentNode = SplitRun((Run) currentNode, e.MatchOffset);
        // This array is used to store all nodes of the match for further removing.
        ArrayList runs = new ArrayList();
        // Find all runs that contain parts of the match string.
        int remainingLength = e.Match.Value.Length;
        while ((remainingLength> 0) &&
            (currentNode != null) &&
            (currentNode.GetText().Length <= remainingLength))
            remainingLength = remainingLength - currentNode.GetText().Length;
            // Select the next Run node.
            // Have to loop because there could be other nodes such as BookmarkStart etc.
            do {
                currentNode = currentNode.NextSibling;
            while ((currentNode != null) && (currentNode.NodeType != NodeType.Run));
        // Split the last run that contains the match if there is any text left.
        if ((currentNode != null) && (remainingLength> 0))
            SplitRun((Run) currentNode, remainingLength);
        // Create Document Buidler aond insert MergeField
        DocumentBuilder builder = new DocumentBuilder(e.MatchNode.Document as Document);
        builder.MoveTo((Run) runs[runs.Count - 1]);
        builder.InsertField("PAGE", "");
        // Now remove all runs in the sequence.
        foreach(Run run in runs)
        // Signal to the replace engine to do nothing because we have already done all what we wanted.
        return ReplaceAction.Skip;