无法获得不同语言的Unicode支持

Question

public PDFFormFillerResult CreateHtmlToPdfMemoryStream(string sHtmlText)
    {
        //Create a stream that we can write to, in this case a MemoryStream
        using (var ms = new MemoryStream())
        {
            //Create an iTextSharp Document which is an abstraction of a PDF but **NOT** a PDF
            var doc = new iTextSharp.text.Document();

            //Create a writer that's bound to our PDF abstraction and our stream
            var writer = PdfWriter.GetInstance(doc, ms);

            //Open the document for writing
            doc.Open();

            var example_html = sHtmlText;

            //Create a new HTMLWorker bound to our document
            var htmlWorker = new iTextSharp.text.html.simpleparser.HTMLWorker(doc);

          FontFactory.Register(Path.Combine(Environment.CurrentDirectory + "\\Library\\arial.ttf"), "Arial");   // just give a path of arial.ttf
            StyleSheet css = new StyleSheet();
            css.LoadTagStyle("body", "face", "Garamond");
            css.LoadTagStyle("body", "encoding", "Identity-H");
            css.LoadTagStyle("body", "size", "12pt");

            htmlWorker.SetStyleSheet(css);
           // htmlWorker.StartDocument();

            //HTMLWorker doesn't read a string directly but instead needs a TextReader (which StringReader subclasses)
            using (var sr = new StringReader(example_html)) // using (TextReader sr = new StreamReader(example_html, Encoding.UTF8))
            {
                //Parse the HTML
                htmlWorker.Parse(sr);
            }

            doc.Close();
            return new PDFFormFillerResult(ms, PDFFormFillerResultType.Success, string.Empty);
        }
    }

我需要输出为ByteStream，因为我正在合并多个文档以在最后创建一个pdf。这适用于英语，但是当我尝试使用俄语，韩语，Combodian等其他语言时，只会显示模板中的英文文本。