Controller.cs

public ActionResult Index()
{
    Document document = new Models.Document();

    MemoryStream ms = new MemoryStream();
    FileStream fs;

    // load the document into a stream
    using (fs = System.IO.File.OpenRead(
        Server.MapPath("/App_Data/documents/document.docx")))
    {
        fs.CopyTo(ms);
        document.BinaryDocument = Convert.ToBase64String(ms.ToArray());
    }
    
    // forward the document to the view
    return View(document);
}