c# vsto savefileas

c#-vsto-saveFileAs.cs

 public void Save()
        {
            Saving = true;
            try
            {
                writeProperties();
                Document doc = getDoc();
                FileInfo f = new FileInfo(doc.FullName);
                String strFileName = String.Format(@"{0}\{1} - v.{2}.{3}.{4}.docx", f.Directory.FullName, DocTitle, Revision, Version, Build);

              
                object missing = System.Reflection.Missing.Value;
                object fileName = strFileName;
                object format = Microsoft.Office.Interop.Word.WdSaveFormat.wdFormatDocumentDefault;

                doc.SaveAs(ref fileName, ref format, ref missing, ref missing,
                           ref missing, ref missing, ref missing, ref missing,
                           ref missing, ref missing, ref missing, ref missing,
                           ref missing, ref missing, ref missing, ref missing);
            }
            catch (Exception ex)
            {


                MessageBox.Show(ex.ToString());
                throw;
            }
            Saving = false;
        }