data.cs

public ActionResult Index()
{
    // set document name to dummy document
    string sDocumentName = Server.MapPath("~/template.docx");

    // create a new TrackedChangeModel
    TrackedChangeModel model = new TrackedChangeModel() {
        DocumentName = sDocumentName
    };

    // use a temporary ServerTextControl to retrieve the
    // changes and to create the thumbnails
    using (ServerTextControl tx = new ServerTextControl())
    {
        tx.Create();

        // load the document
        tx.Load(sDocumentName, StreamType.WordprocessingML);

        // loop through all text parts including headers and footers
        foreach (IFormattedText textPart in tx.TextParts)
        {
            // loop through all changes
            foreach (TXTextControl.TrackedChange trackedChange in textPart.TrackedChanges)
            {
                if (trackedChange.ChangeTime < model.FirstChange) // get first change time stamp
                    model.FirstChange = trackedChange.ChangeTime;

                // create a new TrachedChange object
                Models.TrackedChange tc = new Models.TrackedChange()
                {
                    ChangeTime = trackedChange.ChangeTime,
                    HighlightColor = ColorTranslator.ToHtml(trackedChange.HighlightColor),
                    ChangeKind = (Models.ChangeKind)trackedChange.ChangeKind,
                    Text = trackedChange.Text,
                    UserName = (trackedChange.UserName == "") ? "Unknown User"
                        : trackedChange.UserName
                };

                // highlight the change in the document
                trackedChange.ScrollTo();
                trackedChange.Select();
                textPart.Selection.TextBackColor = Color.Yellow;

                // create a thumbnail of the page and the highlighted change
                tc.Image = ImageToBase64(
                    tx.GetPages().GetItem().GetImage(100, Page.PageContent.All)
                , ImageFormat.Jpeg);

                // add the change to the model
                model.TrackedChanges.Add(tc);
            }
        }
    }

    return View(model);
}