Use replace to add fields

Aspose.Words Product Family
1

I’d like to replace “Page %%PAGE%% of %%NUMPAGES%%” to “Page {PAGE * MERGEFORMAT} of {NUMPAGES * MERGEFORMAT}” at my document. E.g. convert all %%FIELD%% into {FIELD}.

So I took a ReplaceTextWithFields sample and did it like this.

FindReplaceOptions options = new FindReplaceOptions();
options.ReplacingCallback = new ReplaceTextWithFieldHandler();
doc.Range.Replace(new Regex(@"%%(.*?)%%"), "", options);

public class ReplaceTextWithFieldHandler : IReplacingCallback
{
    public ReplaceTextWithFieldHandler()
    {
    }

    public ReplaceAction Replacing(ReplacingArgs args)
    {
        ArrayList runs = FindAndSplitMatchRuns(args);

        // Create DocumentBuilder which is used to insert the field.
        DocumentBuilder builder = new DocumentBuilder((Document)args.MatchNode.Document);
        builder.MoveTo((Run)runs[runs.Count - 1]);

        // Insert the field into the document using the specified field type and the match text as the field name.
        // If the fields you are inserting do not require this extra parameter then it can be removed from the string below.
        builder.InsertField(args.Match.Groups[1].ToString());

        // Now remove all runs in the sequence.
        foreach (Run run in runs)
            run.Remove();

        // Signal to the replace engine to do nothing because we have already done all what we wanted.
        return ReplaceAction.Skip;
    }

    /// <summary>
    /// Finds and splits the match runs and returns them in an ArrayList.
    /// </summary>
    public ArrayList FindAndSplitMatchRuns(ReplacingArgs args)
    {
        // This is a Run node that contains either the beginning or the complete match.
        Node currentNode = args.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 (args.MatchOffset > 0)
            currentNode = SplitRun((Run)currentNode, args.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 = args.Match.Value.Length;
        while (
            (remainingLength > 0) &&
            (currentNode != null) &&
            (currentNode.GetText().Length <= remainingLength))
        {
            runs.Add(currentNode);
            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);
            runs.Add(currentNode);
        }

        return runs;
    }

    /// <summary>
    /// Splits text of the specified run into two runs.
    /// Inserts the new run just after the specified run.
    /// </summary>
    private Run SplitRun(Run run, int position)
    {
        Run afterRun = (Run)run.Clone(true);
        afterRun.Text = run.Text.Substring(position);
        run.Text = run.Text.Substring(0, position);
        run.ParentNode.InsertAfter(afterRun, run);
        return afterRun;

    }
}

And I get an exception at SplitRun.

If I split the text into 2 lines, it does work fine:
“Page %%PAGE%%
of %%NUMPAGES%%”

So I have a feeling that all this splitting somehow corrupts the flow. But I’m not sure why is it even necessary, and what to do to fix it…

2

@emfbd33,

Thanks for your inquiry. Please use FindReplaceOptions.Direction as Backward to fix this issue. Hope this helps you.

FindReplaceOptions options = new FindReplaceOptions();
options.ReplacingCallback = new ReplaceTextWithFieldHandler();
options.Direction = FindReplaceDirection.Backward;
doc.Range.Replace(new Regex(@"%%(.*?)%%"), "", options);
3

wow, that’s the way. thanks!