使用iTextSharp更改导出pdf文件中的默认字体

Question

我在导出pdf文件时使用默认字体时遇到一些问题。我想更改默认字体类型，例如unicode（缅甸）字体。由于打击代码是pdf文件中未显示unicode字体。我的数据包括unicode字体数据还应该如何解决该错误。请告诉我正确的方向。我的代码是

GridView GridView1 = new GridView();
                Response.ContentType = "Application/pdf";
                Response.AddHeader("content-disposition", "attachment; filename = SalesByBranch.pdf");
                Response.Cache.SetCacheability(HttpCacheability.NoCache);
                StringWriter sw = new StringWriter();
                HtmlTextWriter hw = new HtmlTextWriter(sw);
                List<SalesByBranchVM> list = data as List<SalesByBranchVM>;
                GridView1.DataSource = list;
                GridView1.AllowPaging = false;
                GridView1.DataBind();
                GridView1.RenderControl(hw);
                StringReader sr = new StringReader(sw.ToString());
                Document pdfDoc = new Document(PageSize.A4, 10f, 10f, 10f, 0f);
                HTMLWorker htmlparser = new HTMLWorker(pdfDoc);
                PdfWriter.GetInstance(pdfDoc, Response.OutputStream);
                pdfDoc.Open();
                htmlparser.Parse(sr);
                pdfDoc.Close();
                Response.Write(pdfDoc);
                Response.End();

请回复我！