網頁自動登錄和提交POST信息的核心就是分析網頁的源代碼（HTML），在C#中，可以用來提取網頁HTML的組件比較多，常用的用WebBrowser、WebClient、HttpWebRequest這三個。以下就分別用這三種方法來實現：
1、WebBrowser是個"迷你"瀏覽器，其特點是Post時不用關心Cookie、內置JS等問題
WebBrowser是VS2005新提供的組件（其實就是封裝了IE接口），實現POST功能一般在webBrowser的DocumentCompleted中分析HtmlDocument 來實現，代碼如下：
HtmlElement ClickBtn =null;
if (e.Url.ToString().ToLower().IndexOf("xxx.htm") > 0) //登陸頁面
{
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]; //提交按鈕
break;
}
}
}
ClickBtn.InvokeMember("Click"); //執行按扭操作
}
2、WebClient封裝了HTTP的一些類，操作簡單，相較於webBrowser，特點是可以自設代理，缺點是對COOKIE的控制
WebClient的運行全在後台，並且提供了異步操作的能力，這樣很方便並發多個任務，然後等待結果的返回，再逐個處理。多任務異步調用的代碼如下：
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://xxxx.com.cn/tp.asp?Id=129")); //打開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); // 轉化成二進制數組
((WebClient)sender).UploadDataAsync(new Uri("http://xxxxxxy.com.cn/tp.asp?Id=129"), "POST", byteArray);
}
}
private void Pic_UploadDataCompleted2(object sender, UploadDataCompletedEventArgs e)
{
if (e.Error == null)
{
string returnMessage = Encoding.Default.GetString(e.Result);
......
}
}
3、HttpWebRequest較為低層，能實現的功能較多，Cookie操作也很簡單
private bool PostWebRequest()
{
CookieContainer cc = new CookieContainer();
string pos tData = "user=" + strUser + "&pass=" + strPsd;
byte[] byteArray = Encoding.UTF8.GetBytes(postData); // 轉化
HttpWebRequest webRequest2 = (HttpWebRequest)WebRequest.Create(new Uri("http://www.xxxx.com/chk.asp"));
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); //寫入參數
newStream.Close();
HttpWebResponse response2 = (HttpWebResponse)webRequest2.GetResponse();
StreamReader sr2=new StreamReader(response2.GetResponseStream(), Encoding.Default);
string text2 = sr2.ReadToEnd();
......
}
