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; } }
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