GridView导出PDF用itextsharp，就时无法显示中文，大神求解答

[一扁孤舟]

protected void ExportToPDF_Click(object sender, EventArgs e)
{
Response.Clear();

Response.Charset = "GB2312";

StringBuilder sb = new StringBuilder();

StringWriter sw = new StringWriter(sb);

HtmlTextWriter htw = new HtmlTextWriter(sw);



Response.ContentType = "application/pdf";

Response.AddHeader("content-disposition", "attachment; filename=MypdfFile.pdf");

Response.ContentEncoding = System.Text.Encoding.Unicode;



Document document = new Document();

PdfWriter.GetInstance(document, Response.OutputStream);

document.Open();

BaseFont font = BaseFont.CreateFont(@"C:/WINDOWS/Fonts/simhei.ttf", BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);

gvCustomers.RenderControl(htw);

string html = sb.ToString();

XmlTextReader reader = new XmlTextReader(new StringReader(html));

HtmlParser.Parse(document, reader);

document.Close();
sw.Close();

Response.Flush();

Response.End();
}