c# iTextSharp导出PDF

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Threading;
using iTextSharp.text;
using System.IO;
using System.Windows.Forms;
using iTextSharp.text.pdf;

namespace Bmw.Web.BLL
{
    public class OutPDF
    {
        private static System.Drawing.Bitmap bitmap;
        private static string url;
        private static int w = 760, h = 900;
        public static void setBitmap()
        {
            using (WebBrowser wb = new WebBrowser())//应该是new的问题？。。
            {
                wb.Width = w;
                wb.Height = h;
                wb.ScrollBarsEnabled = false;
                
                wb.Navigate(url);
                //确保页面被解析完全
                while (wb.ReadyState != WebBrowserReadyState.Complete)
                {
                    System.Windows.Forms.Application.DoEvents();
                }
                bitmap = new System.Drawing.Bitmap(w, h);
                wb.DrawToBitmap(bitmap, new System.Drawing.Rectangle(0, 0, w, h));
                wb.Dispose();
            }
        }
        public static void CreatPdf()
        {
            Document doc = new Document(PageSize.A4, 9, 18, 36, 36);//左右上下
            MemoryStream ms = new MemoryStream();
            try
            {
                PdfWriter writer = PdfWriter.GetInstance(doc, ms);
                writer.CloseStream = false;
                doc.Open();
                url = "http://localhost:5026/Orders/SeeOneOrder?Order_Id=31";
                Thread thread = new Thread(new ThreadStart(setBitmap));
                thread.SetApartmentState(ApartmentState.STA);
                thread.Start();
                while (thread.IsAlive)
                    Thread.Sleep(100);
                bitmap.Save("t.bmp");

                iTextSharp.text.Image img = iTextSharp.text.Image.GetInstance(bitmap, System.Drawing.Imaging.ImageFormat.Bmp);
                img.ScalePercent(75);//560 630
                doc.Add(img);
            }
            catch (Exception err)
            {
                throw new Exception(err.Message);
            }
            finally
            {
                doc.Close();
                //using (FileStream fs = new FileStream("out.pdf", FileMode.Create))
                //{
                    ms.Position = 0;
                    byte[] bit = new byte[ms.Length];
                    ms.Read(bit, 0, (int)ms.Length);
                    //fs.Write(bit, 0, bit.Length);
                //}
                ViewPdf(ms);
            }
        }
        private static void ViewPdf(Stream fs)
        {

            HttpContext.Current.Response.Clear();
            //中文名的话
            //Response.AppendHeader("Content-Disposition", "attachment;filename=" +
            //             HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8) + ";charset=GB2312");
            HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment;FileName=out.pdf");
            HttpContext.Current.Response.AddHeader("Content-Length", fs.Length.ToString());
            HttpContext.Current.Response.ContentType = "application/pdf";
            long fileLength = fs.Length;
            int size = 10240;//10K一--分块下载，10K为1块
            byte[] readData = new byte[size];
            if (size > fileLength)
                size = Convert.ToInt32(fileLength);
            long fPos = 0;
            bool isEnd = false;
            while (!isEnd)
            {
                if ((fPos + size) >= fileLength)
                {
                    size = Convert.ToInt32(fileLength - fPos);
                    isEnd = true;
                }
                readData = new byte[size];
                fs.Position = fPos;
                fs.Read(readData, 0, size);
                HttpContext.Current.Response.BinaryWrite(readData);
                HttpContext.Current.Response.OutputStream.Flush();
                fPos += size;
            }
            fs.Close();
            HttpContext.Current.Response.OutputStream.Close();
            HttpContext.Current.Response.End();//非常重要，没有这句的话，页面的HTML代码将会保存到文件中
            HttpContext.Current.Response.Close();
        }
    }
}