private void btnASPNET_Click(object sender, EventArgs e)
{
Dictionary<string, string> postParams = new Dictionary<string, string>();
postParams.Add("txtLoginId", "www.cnuunet.com");
postParams.Add("txtPassword", "www.cnuunet.com");
postParams.Add("btnLogin", "Sign in");
textBox1.Text = GetAspNetCodeResponseDataFromWebSite(postParams, "http://www.cnuunet.com/login.aspx", "http://www.cnuunet.com/ProductList.aspx");
}
/// <summary>
/// ASP.net页面登录方式 通过post密码方式读取网页内容
/// 在本页面（login.aspx）的.cs文件内验证用户名和密码。
/// Asp.net验证需要记住本次页面加载的__VIEWSTATE和__EVENTVALIDATION信息，并且需要button按钮的ID和Text信息
/// </summary>
/// <param name="postParams">用户名（用户名文本框的ID和内容）、密码（密码文本框的ID和内容）、summit按钮（button按钮的ID和Text）</param>
/// <param name="getViewStateAndEventValidationLoginUrl">需要验证登陆信息的url</param>
/// <param name="getDataUrl">需要抓取数据的网页url</param>
/// <returns>抓取页面返回的html信息</returns>
private string GetAspNetCodeResponseDataFromWebSite(Dictionary<string, string> postParams, string getViewStateAndEventValidationLoginUrl, string getDataUrl)
{
if (postParams == null || postParams.Keys.Count!=3)
{
string errorMessage = "参数中需要包含如下3个信息，缺一不可。用户名（用户名文本框的ID和内容）、密码（密码文本框的ID和内容）、summit按钮（button按钮的ID和Text）";
MessageBox.Show(errorMessage);
return errorMessage ;
}
try
{
CookieContainer cookieContainer = new CookieContainer();
///////////////////////////////////////////////////
// 1.打开 MyLogin.aspx 页面，获得 GetVeiwState & EventValidation
///////////////////////////////////////////////////
// 设置打开页面的参数
HttpWebRequest request = WebRequest.Create(getViewStateAndEventValidationLoginUrl) as HttpWebRequest;
request.Method = "GET";
request.KeepAlive = false;
// 接收返回的页面
HttpWebResponse response = request.GetResponse() as HttpWebResponse;
System.IO.Stream responseStream = response.GetResponseStream();
System.IO.StreamReader reader = new System.IO.StreamReader(responseStream, Encoding.UTF8);
string srcString = reader.ReadToEnd();
// 获取页面的 VeiwState,分析返回的页面，解析出__VIEWSTATE的值
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,分析返回的页面，解析出__VIEWSTATE的值
string eventValidationFlag = "id=\"__EVENTVALIDATION\" value=\"";
i = srcString.IndexOf(eventValidationFlag) + eventValidationFlag.Length;
j = srcString.IndexOf("\"", i);
string eventValidation = srcString.Substring(i, j - i);
///////////////////////////////////////////////////
// 2.自动填充并提交 Login.aspx 页面，提交Login.aspx页面，来保存Cookie
///////////////////////////////////////////////////
// 将文本转换成 URL 编码字符串
viewState = System.Web.HttpUtility.UrlEncode(viewState);
eventValidation = System.Web.HttpUtility.UrlEncode(eventValidation);
// 要提交的字符串数据。格式形如:user=uesr1&password=123
string postString = "";
foreach (KeyValuePair<string, string> de in postParams)
{
//把提交按钮中的中文字符转换成url格式，以防中文或空格等信息
postString += System.Web.HttpUtility.UrlEncode(de.Key.ToString()) + "=" + System.Web.HttpUtility.UrlEncode(de.Value.ToString()) + "&";
}
postString += string.Format("__VIEWSTATE={0}&__EVENTVALIDATION={1}", viewState, eventValidation);
// 将提交的字符串数据转换成字节数组
byte[] postData = Encoding.ASCII.GetBytes(postString);
// 设置提交的相关参数
request = WebRequest.Create(getViewStateAndEventValidationLoginUrl) as HttpWebRequest;
request.Method = "POST";
request.KeepAlive = false;
request.ContentType = "application/x-www-form-urlencoded";
request.CookieContainer = cookieContainer;
request.ContentLength = postData.Length;
// 提交请求数据
System.IO.Stream outputStream = request.GetRequestStream();
outputStream.Write(postData, 0, postData.Length);
outputStream.Close();
// 接收返回的页面
response = request.GetResponse() as HttpWebResponse;
responseStream = response.GetResponseStream();
reader = new System.IO.StreamReader(responseStream, Encoding.GetEncoding("GB2312"));
srcString = reader.ReadToEnd();
///////////////////////////////////////////////////
// 3.打开需要抓取数据的页面
///////////////////////////////////////////////////
// 设置打开页面的参数
request = WebRequest.Create(getDataUrl) as HttpWebRequest;
request.Method = "GET";
request.KeepAlive = false;
request.CookieContainer = cookieContainer;
// 接收返回的页面
response = request.GetResponse() as HttpWebResponse;
responseStream = response.GetResponseStream();
reader = new System.IO.StreamReader(responseStream, Encoding.UTF8);
srcString = reader.ReadToEnd();
return srcString;
///////////////////////////////////////////////////
// 4.分析返回的页面
///////////////////////////////////////////////////
// ...... ......
}
catch (WebException we)
{
string msg = we.Message;
return msg;
}
}