C#网页自动登录和提交POST信息的多种方法

网页自动登录和提交POST信息的核心就是分析网页的源代码（HTML），在C#中，可以用来提取网页HTML的组件比较多，常用的用WebBrowser、WebClient、HttpWebRequest这三个。
以下就分别用这三种方法来实现：
1、WebBrowser是个"迷你"浏览器，其特点是Post时不用关心Cookie、内置JS等问题
WebBrowser是VS2005新提供的组件（其实就是封装了IE接口），实现POST功能一般在webBrowser的DocumentCompleted中分析HtmlDocument 来实现，代码如下：
                      HtmlElement ClickBtn =null;
                      if (e.Url.ToString().ToLower().IndexOf("http://www.baidu.com/") > 0)      //登陆页面
                        {
                                HtmlDocument doc = webBrowser1.Document;
                                for (int i = 0; i < doc.All.Count ; i++)
                                {
                                        if (doc.All[i].TagName.ToUpper().Equals("INPUT"))
                                        {
                                                switch (doc.All[i].Name)
                                                {
                                                        case "userCtl":
                                                                doc.All[i].InnerText = "user01";
                                                                break;
                                                        case "passCt1":
                                                                doc.All[i].InnerText = "mypass";
                                                                break;
                                                        case "B1":
                                                                ClickBtn = doc.All[i]; //提交按钮
                                                                break;
                                                }
                                        }
                                }
                                ClickBtn.InvokeMember("Click");      //执行按扭操作
                        }
2、WebClient封装了HTTP的一些类，操作简单，相较于webBrowser，特点是可以自设代理，缺点是对COOKIE的控制
WebClient的运行全在后台，并且提供了异步操作的能力，这样很方便并发多个任务，然后等待结果的返回，再逐个处理。多任务异步调用的代码如下：
private void StartLoop(int ProxyNum)
                {
                      WebClient []    wcArray = new WebClient[ProxyNum];    //初始化
                          for (int idArray = 0; idArray< ProxyNum;idArray++)
                        {
                                  wcArray[idArray] = new WebClient();
                                wcArray[idArray].OpenReadCompleted += new OpenReadCompletedEventHandler(Pic_OpenReadCompleted2);
                                wcArray[idArray].UploadDataCompleted += new UploadDataCompletedEventHandler(Pic_UploadDataCompleted2);
                                try
                                {
                                      
                                        wcArray[idArray].Proxy = new WebProxy(proxy[1], port);
                                        wcArray[idArray].OpenReadAsync(new Uri("http://www.baidu.com/")); //打开WEB;
                                        proxy = null;
                                }
                                catch
                                {
                                }
                        }
                }
                private void Pic_OpenReadCompleted2(object sender, OpenReadCompletedEventArgs e)
                {
                                if (e.Error == null)
                                {
                                                        string textData = new StreamReader(e.Result, Encoding.Default).ReadToEnd();    //取返回信息
                                                          ..
                                                            String cookie = ((WebClient)sender).ResponseHeaders["Set-Cookie"];
                                                          ((WebClient)sender).Headers.Add("Content-Type", "application/x-www-form-urlencoded");
                                                        ((WebClient)sender).Headers.Add("Accept-Language", "zh-cn");
                                                        ((WebClient)sender).Headers.Add("Cookie", cookie);
                                                        string postData = ""
                                                        byte[] byteArray = Encoding.UTF8.GetBytes(postData); // 转化成二进制数组
                                                      ((WebClient)sender).UploadDataAsync(new Uri("http://www.baidu.com/"), "POST", byteArray);
                                }
                  }
                private void Pic_UploadDataCompleted2(object sender, UploadDataCompletedEventArgs e)
                {
                                  if (e.Error == null)
                                {
                                        string returnMessage = Encoding.Default.GetString(e.Result);
                                      
                                }
              }


3、HttpWebRequest较为低层，能实现的功能较多，Cookie操作也很简单:

              private bool    PostWebRequest()              
                {
                                      CookieContainer cc = new CookieContainer();
                                        string pos tData = "user=" + strUser + "&pass=" + strPsd;
                                        byte[] byteArray = Encoding.UTF8.GetBytes(postData); // 转化
                                        HttpWebRequest webRequest2 = (HttpWebRequest)WebRequest.Create(new Uri(http://www.baidu.com/));
                                        webRequest2.CookieContainer = cc;
                                        webRequest2.Method = "POST";
                                        webRequest2.ContentType = "application/x-www-form-urlencoded";
                                        webRequest2.ContentLength = byteArray.Length;
                                        Stream newStream = webRequest2.GetRequestStream();
                                        // Send the data.
                                        newStream.Write(byteArray, 0, byteArray.Length);        //写入参数
                                        newStream.Close();
                                        HttpWebResponse response2 = (HttpWebResponse)webRequest2.GetResponse();
                                        StreamReader sr2=new StreamReader(response2.GetResponseStream(), Encoding.Default);
                                        string text2 =    sr2.ReadToEnd();
                                  
                }        
HttpWebRequest 实现， 这个是从网上COPY 的！我以前用相关的代码登录到WWW.ASP.NET上，并且成功post，可惜代码不知道放什么地方了。
HttpWebRequest自动登录网站并获取网站内容（不包含验证码的网站）
可以使用 Visual Sniffer（百度搜索） 来捕捉提交的数据信息：
1. 访问你需要站外提交的页面，比如 CSDN 登陆页 http://www.csdn.net/member/UserLogin.aspx
2. 填写好需要的资料，比如用户名和密码，
3. 打开 Visual Sniffer, 点“开始拦截”
4. 在访问的页面中提交。
5. 等提交成功之后，在 Visual Sniffer 中“停止拦截”
6. 在 Visual Sniffer 的左侧栏的加号中依次点开，右边是它拦截到的内容：

POST http://www.csdn.net/member/UserLogin.aspx HTTP/1.0
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, application/x-shockwave-flash, **
Referer: http://www.csdn.net/member/UserLogin.aspx
Accept-Language: zh-cn
UA-CPU: x86
Pragma: no-cache
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; InfoPath.1)
Host: www.csdn.net
Proxy-Connection: Keep-Alive
Cookie: ASPSESSIONIDAAAATBQC=FMEGGCKDBKHAMMCGKPFDMBFG; ASP.NET_SessionId=lusprmnom05lr445tmteaf55; userid=699879
以上为拦截内容，其中提交数据的参数部分（程序中的：strArgs）如：
__EVENTTARGET=&__EVENTARGUMENT=&__VIEWSTATE=dDwtMTcwMzgxNjQ2Mjs7bDxDU
0ROVXNlckxvZ2luOmNiX1NhdmVTdGF0ZTtDU0ROVXNlckxvZ2luOkltYWdlX0xvZ2luOz4%2Btu
1q2wmRZoAJTi9L73w1zBleylY%3D&CSDNUserLogin%3Atb_UserName=testusername&CSDN
UserLogin%3Atb_Password=testpassword&CSDNUserLogin%3Atb_ExPwd=9232


                protected static string cookieHeader;
                private void Page_Load(object sender, System.EventArgs e)
                {
                        string strReContent = string.Empty;
                        //登录
                        strReContent = PostLogin("http://www.mystand.com.cn/login/submit.jsp提交的页面","提交的参数：userid=hgj0000&password=06045369","引用地址：http://www.mystand.com.cn/");
                        //asp.net登录传递的参数需注意      
                        //strReContent = PostLogin("http://www.mystand.com.cn/login.aspx","__VIEWSTATE=dDwtNjkzMjUyNDczO3Q8O2w8aTwzPjs%2BO2w8dDxwPHA8bDxUZXh0Oz47bDxcZTs%2BPjs%2BOzs%2BOz4%2BOz6aX2dtqkJTK%2BKbNPsjd7Op%2Fl26Iw%3D%3D&txtUserName=hxf&txtPassword=hxf0000&btnEnter=%E7%99%BB%E5%BD%95","http://www.mystand.com.cn/login.aspx");
                        //获取页面
                        strReContent = GetPage("http://www.mystand.com.cn/company/getdata.jsp?code=","引用地址：http://www.mystand.com.cn/");
                        //strReContent = GetPage("http://www.mystand.com.cn/Modules/index.aspx","http://www.mystand.com.cn/login.aspx");
                        //可以对获得的内容进行处理：strReContent
                }
                ///

                /// 功能描述：模拟登录页面，提交登录数据进行登录，并记录Header中的cookie
                ///

                /// 登录数据提交的页面地址                /// 用户登录数据                /// 引用地址                /// 可以返回页面内容或不返回                public static string PostLogin(string strURL,string strArgs,string strReferer)
                {
                        string strResult = "";
                        HttpWebRequest myHttpWebRequest = (HttpWebRequest)WebRequest.Create(strURL);
                        myHttpWebRequest.AllowAutoRedirect = true;
                        myHttpWebRequest.KeepAlive = true;
                        myHttpWebRequest.Accept = "image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-excel, application/msword, application/x-shockwave-flash, *///

                /// 功能描述：在PostLogin成功登录后记录下Headers中的cookie，然后获取此网站上其他页面的内容
                ///

                /// 获取网站的某页面的地址                /// 引用的地址                /// 返回页面内容                public static string GetPage(string strURL,string strReferer)
                {
                        string strResult = "";
                        HttpWebRequest myHttpWebRequest = (HttpWebRequest)WebRequest.Create(strURL);
                        myHttpWebRequest.ContentType = "text/html";
                        myHttpWebRequest.Method = "GET";
                        myHttpWebRequest.Referer = strReferer;
                        myHttpWebRequest.Headers.Add("cookie:"+ cookieHeader);
                        HttpWebResponse response = null;
                        System.IO.StreamReader sr = null;
                        response = (HttpWebResponse)myHttpWebRequest.GetResponse();
                        sr = new System.IO.StreamReader(response.GetResponseStream(), Encoding.GetEncoding("gb2312"));        //        //utf-8
                        strResult = sr.ReadToEnd();
                        return strResult;
                }
技术应用——网页自动登录（提交Post内容）的用途很多，如验证身份、程序升级、网络投票等，以下是用C#实现的方法.
未解决问题——目前最大问题无法绕过验证码——我曾经和同事讨论图片的算法，基本上很难识别，网上也有很多识别验证码的例子，但是对于简单的噪声还是可以的，可是对于复杂的就一点用都没有了！到目前为止，我没有测试成功过！如果你有测试成功过，请帖代码，我们一起研究研究。