首先打开网站，查看源文件，找到他的登录表单部分。

比如：

用户名：	maxlength="40" size="23" name="username" id="username" />
密　码：	maxlength="40" size="23" name="passwd" type="password" id="passwd" />

从以上表单可以看出，表单提交的方法是：POST，提交至loginMain.jsp处理,共有两个表单项即：username、passwd

下面是C#模仿登录程序:Login.cs

using System;

using System.Data;

using System.Net;
using System.Text;

using System.IO;

using System.Text.RegularExpressions;

///

/// 登录网站并获取Cookies

///

/// 成功登录的Cookie信息

public static CookieContainer Get_Login()

{

CookieContainer cc = new CookieContainer();

string FormURL="http://blog.hnce.net/loginMain.jsp"; //处理表单的绝对URL地址

string FormData = "username=slick&passwd=hedy12345"; //表单需要提交的参数，注意改为你已注册的信息。

ASCIIEncoding encoding = new ASCIIEncoding();

byte[] data = encoding.GetBytes(FormData);

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(FormURL);

request.Method = "POST"; //数据提交方式

request.ContentType = "application/x-www-form-urlencoded";

request.ContentLength = data.Length;

request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322)";

//模拟一个UserAgent

Stream newStream = request.GetRequestStream();

newStream.Write(data, 0, data.Length);

newStream.Close();

request.CookieContainer = cc;

HttpWebResponse response = (HttpWebResponse)request.GetResponse();

cc.Add(response.Cookies);

Stream stream = response.GetResponseStream();

string WebContent = new StreamReader(stream, System.Text.Encoding.Default).ReadToEnd();

return cc;

}

调用以上的方法来获取需要登录才能查看的内容。

CookieContainer cc = new CookieContainer();

cc = Login.Get_Login(); //获取登录Cookies

string PhotoClassURL = "http://blog.hnce.net/xxx.jsp";

HttpWebRequest Myrequest = (HttpWebRequest)WebRequest.Create(PhotoClassURL);

Myrequest.CookieContainer = cc;

HttpWebResponse Myresponse = (HttpWebResponse)Myrequest.GetResponse();

cc.Add(Myresponse.Cookies);

Stream Mystream = Myresponse.GetResponseStream();

string sHtml = new StreamReader(Mystream, System.Text.Encoding.Default).ReadToEnd();

sHtml即为你登录之后看到的内容。

ITPub博客

C# 在采集数据时的验证与登录处理