网页模拟登陆

string indata="num1=yemian";
string outdata="";
string url ="http://localhost/sdf/bussiness.aspx";
CookieContainer myCookieContainer=new CookieContainer();
//新建一个CookieContainer来存放Cookie集合
HttpWebRequest myHttpWebRequest=(HttpWebRequest)WebRequest.Create(url);
//新建一个HttpWebRequest
myHttpWebRequest.ContentType="application/x-www-form-urlencoded";
myHttpWebRequest.ContentLength=indata.Length;
myHttpWebRequest.Method="POST";

myHttpWebRequest.CookieContainer=myCookieContainer;
//设置HttpWebRequest的CookieContainer为刚才建立的那个myCookieContainer
Stream myRequestStream=myHttpWebRequest.GetRequestStream();
StreamWriter myStreamWriter=new StreamWriter(myRequestStream,Encoding.GetEncoding("gb2312"));
myStreamWriter.Write(indata);
//把数据写入HttpWebRequest的Request流

myStreamWriter.Close();
myRequestStream.Close();
//关闭打开对象
HttpWebResponse myHttpWebResponse=(HttpWebResponse)myHttpWebRequest.GetResponse();
//新建一个HttpWebResponse
myHttpWebResponse.Cookies=myCookieContainer.GetCookies(myHttpWebRequest.RequestUri);
//获取一个包含url的Cookie集合的CookieCollection
Stream myResponseStream=myHttpWebResponse.GetResponseStream();
StreamReader myStreamReader=new StreamReader(myResponseStream,Encoding.GetEncoding("gb2312"));
outdata=myStreamReader.ReadToEnd();
//把数据从HttpWebResponse的Response流中读出
myStreamReader.Close();
myResponseStream.Close();
Response.Write(outdata);
//显示"登录"

//拿到了Cookie，再进行请求就能直接读取到登录后的内容了
myHttpWebRequest=(HttpWebRequest)WebRequest.Create(url);
myHttpWebRequest.CookieContainer=myCookieContainer; //*
//刚才那个CookieContainer已经存有了Cookie,把它附加到HttpWebRequest中则能直接通过验证
myHttpWebResponse=(HttpWebResponse)myHttpWebRequest.GetResponse();
myHttpWebResponse.Cookies=myCookieContainer.GetCookies(myHttpWebRequest.RequestUri);
myResponseStream=myHttpWebResponse.GetResponseStream();
myStreamReader=new StreamReader(myResponseStream,Encoding.GetEncoding("gb2312"));
outdata=myStreamReader.ReadToEnd();
myStreamReader.Close();
myResponseStream.Close();
Response.Write("<br>"+outdata);

try
{
// 要提交表单的URI字符串。
string uriString = "http://localhost:1165/WebTest/MyLogin.aspx";

///////////////////////////////////////
// 打开页面
///////////////////////////////////////
WebClient webClient = new WebClient();
byte[] responseData = webClient.DownloadData(uriString);
string srcString = Encoding.UTF8.GetString(responseData);

///////////////////////////////////////
// 填写页面并提交
///////////////////////////////////////
webClient = new WebClient();
webClient.Headers.Add("Content-Type", "application/x-www-form-urlencoded");

// 获取页面的 VeiwState
string viewStateFlag = "id=\"__VIEWSTATE\" value=\"";
int i = srcString.IndexOf(viewStateFlag) + viewStateFlag.Length;
int j = srcString.IndexOf("\"",i);
string viewState = srcString.Substring(i, j-i);

// 获取页面的 EventValidation
string eventValidationFlag = "id=\"__EVENTVALIDATION\" value=\"";
i = srcString.IndexOf(eventValidationFlag) + eventValidationFlag.Length;
j = srcString.IndexOf("\"", i);
string eventValidation = srcString.Substring(i, j - i);

// 提交按钮的文本
string submitButton = "登录";

viewState = System.Web.HttpUtility.UrlEncode(viewState);
eventValidation = System.Web.HttpUtility.UrlEncode(eventValidation);
submitButton = System.Web.HttpUtility.UrlEncode(submitButton);

// 要提交的字符串数据。格式形如:user=uesr1&password=123
string postString = "userName=1&password=1" + "&loginButton=" + submitButton + "&__VIEWSTATE=" + viewState + "&__EVENTVALIDATION=" + eventValidation;
// 将字符串转换成字节数组
byte[] postData = Encoding.ASCII.GetBytes(postString);
// 上传数据，返回页面的字节数组
responseData = webClient.UploadData(uriString, "POST", postData);
// 将返回的将字节数组转换成字符串(HTML);
// ASP.NET 返回的页面一般是Unicode,如果是简体中文应使用
// Encoding.GetEncoding("GB2312").GetString(responseData)
srcString = Encoding.UTF8.GetString(responseData);

///////////////////////////////////////
// 分析返回的页面
///////////////////////////////////////
//
}
catch (WebException we)
{
string msg = we.Message;
}