Eric White's Blog

Hi Eric,

I am replacing variables in docx templates with values in a Windows Service. To do this I use TextReplacer.SearchAndReplace. It turns out some of our customers have been using Revision Tracking with their templates and TextReplacer throws when it detects Revision Tracking elements. I’d like to handle this in our service.

I have tried removing the elements which ends up with an NullReferenceException:

System.NullReferenceException: Object reference not set to an instance of an object.
at OpenXmlPowerTools.PtOpenXmlExtensions.GetXDocument(OpenXmlPart part)

Code:

private void ProcessRevisionTracking(WordprocessingDocument wordDoc)
        {
            //var revisionTrackingOn = RevisionAccepter.HasTrackedRevisions(wordDoc);

            //RevisionAccepter.P
            var revisionTrackingElements = wordDoc.MainDocumentPart.DocumentSettingsPart.Settings.Descendants<TrackRevisions>();

            var revisionTrackingOn = revisionTrackingElements
                                        .Any(rte => rte.Val = new DocumentFormat.OpenXml.OnOffValue(true));

            if (revisionTrackingOn)
            {
                logger.LogDebug("Revision tracking " + (revisionTrackingOn ? "detected" : "NOT enabled"));
                foreach (var rte in revisionTrackingElements)
                    rte.Remove();
            

            List<OpenXmlPart> parts = new List<OpenXmlPart>();

            parts.Add(wordDoc.MainDocumentPart);
            parts.AddRange(wordDoc.MainDocumentPart.HeaderParts);
            parts.AddRange(wordDoc.MainDocumentPart.FooterParts);
            parts.Add(wordDoc.MainDocumentPart.EndnotesPart);
                parts.Add(wordDoc.MainDocumentPart.FootnotesPart);

            foreach (var part in parts)
            {
                ProcessRevisionTracking(part);
            }

           // wordDoc.MainDocumentPart.Document.Save();

            logger.LogDebug(String.Format("Revision elements still found? - {0}", RevisionAccepter.HasTrackedRevisions(wordDoc)));
            }
            else
                logger.LogDebug("Revision tracking NOT detected");
        }

        private void ProcessRevisionTracking(OpenXmlPart part)
        {

                //var matchNames = RevisionAccepter.TrackedRevisionsElements

                var revisionElements = part.GetXDocument().Descendants()
                            .Where(desc => RevisionAccepter.TrackedRevisionsElements.Contains(desc.Name))
                            .ToArray();

                logger.LogDebug(revisionElements.Length + " revision elements found to remove.");
                foreach (var elem in revisionElements)
                {
                    elem.Remove();
                }

        }

I came across this page https://msdn.microsoft.com/en-us/library/ee836138(v=office.12).aspx#AcceptRevisions_RemovingElements which sounds like I’d need to do some complicated collapsing versus removing. Do you have any advice on how to easily replace the text or is it a case of me coding everything mentioned in that article? I don’t need Revision Tracking in the output document (but can have it if it’s easier), but I would need all the normal document elements.

I was also looking at the source code of https://github.com/VisualOn/OpenXmlPowerTools/blob/master/RevisionAccepter.cs method public static bool PartHasTrackedRevisions(OpenXmlPart part). I don’t understand how some of those elements that don’t sound RevisionTracking related indicate tracking is in use. For instance is the existence of a W.cellDel really enough to signal revision tracking is being used and that element relates to that?

• This topic was modified 8 years, 2 months ago by  AlanSMac. Reason: Code did not format correctly