在导出html时添加CSS

我想导出一个div格式的pdf样式使用代码:

Response.ContentType = "application/pdf";
Response.AddHeader("content-disposition", "attachment;filename=" + Fullname.Text + ".pdf");
Response.Cache.SetCacheability(HttpCacheability.NoCache);
var cssText = System.IO.File.ReadAllText(Server.MapPath("/css/bootstrap.css"));
var memoryStream = new MemoryStream();
StringWriter stringWriter = new StringWriter();
HtmlTextWriter htmlTextWriter = new HtmlTextWriter(stringWriter);
pfd.RenderControl(htmlTextWriter);
StringReader stringReader = new StringReader(stringWriter.ToString().Replace("<br>", "<br/>").Replace("<td>", "<td/>").Replace("<tr>", "<tr/>").Replace("<td>", "<td/>"));
Document Doc = new Document(PageSize.A4, 10f, 10f, 100f, 0f);
PdfWriter writer = PdfWriter.GetInstance(Doc, Response.OutputStream);
Doc.Open();
XMLWorkerHelper.GetInstance().ParseXHtml(writer, Doc, stringReader);
Doc.Close();
Response.Write(Doc);
Response.End();

如何将css文件附加到pdf以在HTML中保持相同的外观?

using iTextSharp.text;
using iTextSharp.text.pdf;
using iTextSharp.tool.xml;

byte[] pdf; // result will be here
var cssText = File.ReadAllText(MapPath("~/css/style.css"));
var html = File.ReadAllText(MapPath("~/css/index.html"));
using (var memoryStream = new MemoryStream())
{
        var document = new Document(PageSize.A4, 20, 20, 30, 30);
        var writer = PdfWriter.GetInstance(document, memoryStream);
        document.Open();
        using (var cssMemoryStream = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(cssText)))
        {
            using (var htmlMemoryStream = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(html)))
            {
                XMLWorkerHelper.GetInstance().ParseXHtml(writer, document, htmlMemoryStream, cssMemoryStream);
            }
        }
        document.Close();
        pdf = memoryStream.ToArray();
}