controller.cs

using myFirstAzureWebApp.Models;
using System;
using System.Data;
using System.Web.Mvc;

namespace myFirstAzureWebApp.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            using (TXTextControl.ServerTextControl tx = new TXTextControl.ServerTextControl())
            {
                tx.Create();
                
                // load MS Word merge fields and included merge blocks
                TXTextControl.LoadSettings ls = new TXTextControl.LoadSettings()
                {
                    ApplicationFieldFormat = TXTextControl.ApplicationFieldFormat.MSWord,
                    LoadSubTextParts = true
                };

                // load the template
                tx.Load(Server.MapPath("~/App_Data/invoice.docx"), 
                    TXTextControl.StreamType.WordprocessingML, ls);

                using (TXTextControl.DocumentServer.MailMerge mailMerge = 
                    new TXTextControl.DocumentServer.MailMerge())
                {
                    mailMerge.TextComponent = tx;

                    DataSet ds = new DataSet();
                    ds.ReadXml(Server.MapPath("~/App_Data/sample_db.xml"), XmlReadMode.Auto);

                    // merge data into template
                    mailMerge.Merge(ds.Tables[0]);

                    byte[] data = null;
                    tx.Save(out data, TXTextControl.BinaryStreamType.InternalUnicodeFormat);

                    // return the document and the document name
                    DocumentView documentView = new DocumentView()
                    {
                        DocumentData = Convert.ToBase64String(data),
                        DocumentName = ls.LoadedFile
                    };

                    return View(documentView);
                }
            }
        }
    }
}