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[ASP.net教程]c#使用WebClient登录网站抓取登录后的网页


C#登录网站实际上就是模拟浏览器提交表单,然后记录浏览器响应返回的会话Cookie值,再次发送请求时带着这个会话cookie值去请求就可以实现模拟登录的效果了。

如下类CookieAwareWebClient实现在发送请求时都带着cookie。

public class CookieAwareWebClient : WebClient{/* 何问起 hwq2.com */  private CookieContainer cookie = new CookieContainer();  protected override WebRequest GetWebRequest(Uri address)  {    WebRequest request = base.GetWebRequest(address);    if (request is HttpWebRequest)    {      (request as HttpWebRequest).CookieContainer = cookie;    }    return request;  }}/* 何问起 hovertree.com */

如下是模拟表单提交登录的使用示例:

var client = new CookieAwareWebClient();client.BaseAddress = @"https://hovertree.net/any/base/url/";var loginData = new NameValueCollection();loginData.Add("login", "YourLogin");loginData.Add("password", "YourPassword");client.UploadValues("login.php", "POST", loginData);//Now you are logged in and can request pages  string htmlSource = client.DownloadString("index.php");/* 何问起 hwq2.com */

推荐:http://www.cnblogs.com/roucheng/p/csharpfetch.html