问题：有的网站的相关内容必须要在登录后才可以查看，其登录信息保存在session变量之中。这样，使用asphttp等组件就难以正确得到所要的信息。
解决：使用asp.net中的httprequest和httpresponse来实现。
要点：
1。 通过附加一个cookiecontainer到httprequest对象中，可以得到登录后返回的代表SESSION ID的COOKIE。 见Login方法
2。 将此COOKIE包含在一个cookiecontainer中并附加到另一个HTTPREQUEST请求中，则可以实现SESSION的还原。见getPage方法
源程序如下：
getHttpInfo.aspx:
<%@ Page language="c#" Codebehind="getHttpInfo.aspx.cs" AutoEventWireup="false" Inherits="PdfTest.getHttpInfo" %>
getHttpInfo.aspx.cs:
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
//using System.Data.OleDb;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Net;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;
using Microsoft.Data.Odbc;
namespace PdfTest
{
///
/// Summary description for WebForm1.
///
public class getHttpInfo : System.Web.UI.Page
{
protected static string cookieheader;
private void Page_Load(object sender, System.EventArgs e)
{
// Put user code to initialize the page here
string strResult;
if (HttpContext.Current.Application["cookieheader"] != null)
{
cookieheader = (string)HttpContext.Current.Application["cookieheader"];
}
else
{
//Login into the website and keep the cookie for the session in the application variable
string strLogin = Login("http://www.thesiteyouwanttovisit/theloginpage.asp", "Action=&USERID=&Password=") ;
}
strResult = getPage("http://www.thesiteyouwanttovisit/theloginpage.asp", "Action=&data=") ;
//Write the result to htm file
FileStream htmFile = new FileStream("c:\save.htm", FileMode.OpenOrCreate);
StreamWriter sw = new StreamWriter(htmFile);
sw.Write(strResult);
sw.Close();
htmFile.Close();
// output the result
Response.Write(strResult);
}
public static string Login(String url, String paramList)
{
HttpWebResponse res = null;
string strResult="";
try
{
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded";
req.AllowAutoRedirect = false;
CookieContainer cookieCon = new CookieContainer();
req.CookieContainer = cookieCon;
StringBuilder UrlEncoded = new StringBuilder();
Char[] reserved = {'?', '=', '&'};
byte[] SomeBytes = null;
if (paramList != null)
{
int i=0, j;
while(i { j=paramList.IndexOfAny(reserved, i); if (j==-1) { UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, paramList.Length-i))); break; } UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, j-i))); UrlEncoded.Append(paramList.Substring(j,1)); i = j+1; } SomeBytes = Encoding.UTF8.GetBytes(UrlEncoded.ToString()); req.ContentLength = SomeBytes.Length; Stream newStream = req.GetRequestStream(); newStream.Write(SomeBytes, 0, SomeBytes.Length); newStream.Close(); } else { req.ContentLength = 0; } res = (HttpWebResponse)req.GetResponse(); cookieheader = req.CookieContainer.GetCookieHeader(new Uri(url)); HttpContext.Current.Application.Lock(); HttpContext.Current.Application["cookieheader"] = cookieheader; HttpContext.Current.Application.UnLock(); Stream ReceiveStream = res.GetResponseStream(); Encoding encode = System.Text.Encoding.GetEncoding("utf-8"); StreamReader sr = new StreamReader( ReceiveStream, encode ); Char[] read = new Char[256]; int count = sr.Read( read, 0, 256 ); while (count > 0) { String str = new String(read, 0, count); strResult += str; count = sr.Read(read, 0, 256); } } catch(Exception e) { strResult = e.ToString(); } finally { if ( res != null ) { res.Close(); } } return strResult; } public static string getPage(String url, String paramList) { HttpWebResponse res = null; string strResult = ""; try { HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url); req.Method = "POST"; req.KeepAlive = true; req.ContentType = "application/x-www-form-urlencoded"; CookieContainer cookieCon = new CookieContainer(); req.CookieContainer = cookieCon; req.CookieContainer.SetCookies(new Uri(url),cookieheader); StringBuilder UrlEncoded = new StringBuilder(); Char[] reserved = {'?', '=', '&'}; byte[] SomeBytes = null; if (paramList != null) { int i=0, j; while(i { j=paramList.IndexOfAny(reserved, i); if (j==-1) { UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, paramList.Length-i))); break; } UrlEncoded.Append(HttpUtility.UrlEncode(paramList.Substring(i, j-i))); UrlEncoded.Append(paramList.Substring(j,1)); i = j+1; } SomeBytes = Encoding.UTF8.GetBytes(UrlEncoded.ToString()); req.ContentLength = SomeBytes.Length; Stream newStream = req.GetRequestStream(); newStream.Write(SomeBytes, 0, SomeBytes.Length); newStream.Close(); } else { req.ContentLength = 0; } res = (HttpWebResponse)req.GetResponse(); Stream ReceiveStream = res.GetResponseStream(); Encoding encode = System.Text.Encoding.GetEncoding("utf-8"); StreamReader sr = new StreamReader( ReceiveStream, encode ); Char[] read = new Char[256]; int count = sr.Read( read, 0, 256 ); while (count > 0) { String str = new String(read, 0, count); strResult += str; count = sr.Read(read, 0, 256); } } catch(Exception e) { strResult = e.ToString(); } finally { if ( res != null ) { res.Close(); } } return strResult; } #region Web Form Designer generated code override protected void OnInit(EventArgs e) { // // CODEGEN: This call is required by the ASP.NET Web Form Designer. // InitializeComponent(); base.OnInit(e); } /// /// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// private void InitializeComponent() { this.Load += new System.EventHandler(this.Page_Load); } #endregion } }