动态页面静态化

下面是一个页面转换的类，该类通过静态函数Changfile()来实现，然后配合IIS Rewrite实现动态页面到静态页面的转换，并能主动控制页面刷新。

using System; 
using System.Data; 
using System.Configuration; 
using System.Web; 
using System.Web.Security; 
using System.Web.UI; 
using System.Web.UI.WebControls; 
using System.Web.UI.WebControls.WebParts; 
using System.Web.UI.HtmlControls; 
using System.Text; 
using System.IO; 

/// <summary>
/// Summary description for HtmlProxy
/// </summary>
public class HtmlProxy
{
    public HtmlProxy()
    {
    }

    public static bool ChangeFile(int id)
    {
        string filename = HttpContext.Current.Server.MapPath("Post_" + id + ".html"); 
        //尝试读取已有文件 
        Stream st = GetFileStream(filename); 
        //如果文件存在并且读取成功 
        if (st != null)
        {
            using (st)
            {
                StreamToStream(st, HttpContext.Current.Response.OutputStream); 
                return true; 
                //Response.End(); 
            }
        }
        else
        {
            StringWriter sw = new StringWriter(); 
            HttpContext.Current.Server.Execute("ForumDetail.aspx?PID=" + id, sw); 

            string content = sw.ToString(); 
            //写进文件
            try
            {
                using (FileStream fs = new FileStream(filename, FileMode.Create, FileAccess.Write, FileShare.Write))
                {
                    using (StreamWriter stw = new StreamWriter(fs, HttpContext.Current.Response.ContentEncoding))
                    {       
                        stw.Write(content); 
                    }
                }
　              return true; 
            }
            catch 
            { 
                return false; 
            }
        }
    }

    private static Stream GetFileStream(string filename)
    {
        try
        {
            DateTime dt = File.GetLastWriteTime(filename); 
            TimeSpan ts = dt - DateTime.Now; 
            if (ts.TotalHours >1)
            {
                //一小时后过期
                return null; 
            }
            return new FileStream(filename, FileMode.Open, FileAccess.Read, FileShare.Read); 
        }
        catch 
        { 
            return null; 
        }
    }

    static public void StreamToStream(Stream src, Stream dst)
    {
　　    byte[] buf = new byte[4096]; 
　　    while (true)
        {
            int c = src.Read(buf, 0, buf.Length); 
            if (c == 0)
            return; 
            dst.Write(buf, 0, c); 
　      }
    }
}

//在页面文件中，ForURL.aspx的后台代码如下：
protected void Page_Load(object sender, EventArgs e)
{
    try
    {
        int id = int.Parse(Request.QueryString["PID"]); 
        if(HtmlProxy.ChangeFile(id))
        {
　          Response.Redirect("Post_" + id + ".html"); 
        }
　      else
        {
　          Response.Write("文件读取错误！"); 
        }
    }
　  catch { }
}