。Net做這個就容易多了，重寫Filter類就可以了。
用法：
if(Session["big5"].ToString()=="2"){Response.Filter = new DreamZone.Core.CG2BFilter(Response.Filter);}
 
CG2BFilter.cs文件如下：
using System;
using System.Text;
using System.Text.RegularExpressions;
using System.IO;
using System.Web;
namespace DreamZone.Core
{
/// <summary>
/// CG2BFilter 的摘要說明。
/// </summary>
 
  public class CG2BFilter : Stream
  {
  Stream          responseStream;
  long            position;
  StringBuilder  responseHtml;
  public CG2BFilter (Stream inputStream)
  {
    responseStream = inputStream;
    responseHtml = new StringBuilder ();
  }
  #region Filter overrides
  public override bool CanRead
  {
    get { return true;}
  }
  public override bool CanSeek
  {
    get { return true; }
  }
  public override bool CanWrite
  {
    get { return true; }
  }
  public override void Close()
  {
    responseStream.Close ();
  }
  public override void Flush()
  {
    responseStream.Flush ();
  }
  public override long Length
  {
    get { return 0; }
  }
  public override long Position
  {
    get { return position; }
    set { position = value; }
  }
  public override long Seek(long offset, SeekOrigin origin)
  {
    return responseStream.Seek (offset, origin);
  }
  public override void SetLength(long length)
  {
    responseStream.SetLength (length);
  }
  public override int Read(byte[] buffer, int offset, int count)
  {
    return responseStream.Read (buffer, offset, count);
  }
  #endregion
  #region 轉(zhuǎn)換任務(wù)
  public override void Write(byte[] buffer, int offset, int count)
  {
    string strBuffer = System.Text.UTF8Encoding.UTF8.GetString (buffer, offset, count);
    string  finalHtml = Simplified2Traditional(strBuffer);   
    byte[] data = System.Text.UTF8Encoding.UTF8.GetBytes (finalHtml);       
    responseStream.Write (data, 0, data.Length);           
     
  }
  #endregion
#region 自定義函數(shù)
  public  string Traditional2Simplified( string str)
  { //繁體轉(zhuǎn)簡體
    return(Microsoft.VisualBasic.Strings.StrConv(str, Microsoft.VisualBasic.VbStrConv.SimplifiedChinese,0));
   
  }
  public  string Simplified2Traditional( string str)
  { //簡體轉(zhuǎn)繁體
    return(Microsoft.VisualBasic.Strings.StrConv(str as String, Microsoft.VisualBasic.VbStrConv.TraditionalChinese,0));
 
  }
#endregion
  }
}