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" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<title>WebForm1</title>
<meta content="Microsoft Visual Studio 7.0" name="GENERATOR">
<meta content="C#" name="CODE_LANGUAGE">
<meta content="JavaScript" name="vs_defaultClientScript">
<meta content="http://schemas.microsoft.com/intellisense/ie5" name="vs_targetSchema">
</HEAD>
<body>
<form id="Form1" method="post" runat="server">
</form>
</body>
</HTML>
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>
/// Summary description for WebForm1.
/// </summary>
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<paramList.Length)
{
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<paramList.Length)
{
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);
}
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.Load += new System.EventHandler(this.Page_Load);
}
#endregion
}
}
//通过Post发送的数据
string payload="chkbook=book&keyword=管理";
WebRequest req = WebRequest.Create("http://localhost/pceo/Search.aspx");
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded";
StringBuilder UrlEncoded = new StringBuilder();
Char[] reserved = {'?', '=', '&'};
byte[] SomeBytes = null;
if (payload != null)
{
int i=0, j;
while(i<payload.Length)
{
j=payload.IndexOfAny(reserved, i);
if (j==-1)
{
UrlEncoded.Append(HttpUtility.UrlEncode(payload.Substring(i, payload.Length-i),System.Text .Encoding .GetEncoding ("gb2312")));
break;
}
UrlEncoded.Append(HttpUtility.UrlEncode(payload.Substring(i, j-i),System.Text .Encoding .GetEncoding ("gb2312")));
UrlEncoded.Append(payload.Substring(j,1));
i = j+1;
}
SomeBytes = Encoding.Default.GetBytes(UrlEncoded.ToString());
req.ContentLength = SomeBytes.Length;
Stream newStream = req.GetRequestStream();
newStream.Write(SomeBytes, 0, SomeBytes.Length);
newStream.Close();
}
else
{
req.ContentLength = 0;
}
try
{
WebResponse result = req.GetResponse();
Stream ReceiveStream = result.GetResponseStream();
Byte[] read = new Byte[512];
int bytes = ReceiveStream.Read(read, 0, 512);
txtHTML.InnerHtml = "";
while (bytes > 0)
{
// 注意：
// 下面假定响应使用 UTF-8 作为编码方式。
// 如果内容以 ANSI 代码页形式（例如，932）发送，则使用类似下面的语句：
// Encoding encode = System.Text.Encoding.GetEncoding("shift-jis");
Encoding encode = System.Text.Encoding.GetEncoding("gb2312");
txtHTML.InnerHtml = txtHTML.InnerHtml + encode.GetString(read, 0, bytes);
bytes = ReceiveStream.Read(read, 0, 512);
}
}
catch(Exception)
{
txtHTML.InnerHtml = "检索页时出错";
}
最近有个朋友离开IT行业二年的朋友说要实现用程序向某个网站的页面上传数据，他是意思是每天有几十条数据要在网站页面上填写，很烦，最好用程序来写。网站页面是用POST传递的，同时没有验证码之类的东东，只有一点限制就是5分种内不能填写二次记录。这一切都好办。
using System.Web;
using System.Net;
using System.Text;
using System.IO;
//创建对某个网站页面的请求
HttpWebRequest myRequest = (HttpWebRequest )WebRequest.Create("http://www.knowsky.com/a.asp")
//上传的数据，”TextBox1“这些东东是网站页面里的控件ID，如果要上传多个值也是用&来分隔
string postData="TextBox1="+this.textBox1.Text+"&TextBox2="+this.textBox2.Text+"
&TextBox3="+this.textBox3.Text+"&TextBox4="+this.textBox4.Text;
ASCIIEncoding encoding=new ASCIIEncoding();
byte[] byte1=encoding.GetBytes(postData);//最终编码后要上传的数据
// Set the content type of the data being posted.
myRequest.ContentType="application/x-www-form-urlencoded";
myRequest.Method="post";//post上传方式
// Set the content length of the string being posted.
myRequest.ContentLength=postData.Length;
Stream newStream=myRequest.GetRequestStream();
newStream.Write(byte1,0,byte1.Length);
一切就OK了，如果你想上传后看到网站的内容的话，可以在程序里放一个IE控件，使用
axWebBrowser1.Navigate("http://www.knowsky.com/a.asp")；
axWebBrowser1.Refresh2();