C#抓取网页的几种方法
来源：http://blog.csdn.net/jhl52771/article/details/8348443
方法1 
/// <summary>
/// 用HttpWebRequest取得网页源码
/// 对于带BOM的网页很有效，不管是什么编码都能正确识别
/// </summary>
/// <param name="url">网页地址" </param>
/// <returns>返回网页源文件</returns>
public static string GetHtmlSource2(string url)
{
//处理内容
string html = "";
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.Accept = "*/*"; //接受任意文件
request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.1.4322)"; // 模拟使用IE在浏览 http://www.52mvc.com
request.AllowAutoRedirect = true;//是否允许302
//request.CookieContainer = new CookieContainer();//cookie容器，
request.Referer = url; //当前页面的引用
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
Stream stream = response.GetResponseStream();
StreamReader reader = new StreamReader(stream, Encoding.Default);
html = reader.ReadToEnd();
stream.Close();
return html;
}
方法2–
using
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.IO;
using System.Text;
using System.Net;
namespace MySql
{
    public class GetHttpData
    {
        public static string GetHttpData2(string Url)
        {
            string sException =
            string sRslt =
            WebResponse oWebRps =
            WebRequest oWebRqst = WebRequest.Create(Url);
            oWebRqst.Timeout =
            try
            {
                oWebRps = oWebRqst.GetResponse();
            }
            catch (WebException e)
            {
                sException = e.Message.ToString();
            }
            catch (Exception e)
            {
                sException = e.ToString();
            }
            finally
            {
                if (oWebRps != null)
                {
                    StreamReader oStreamRd = new StreamReader(oWebRps.GetResponseStream(), Encoding.GetEncoding(“utf-8”));
                   sRslt = oStreamRd.ReadToEnd();
                    oStreamRd.Close();
                    oWebRps.Close();
                }
           }
            return
        }
    }
}
{–写法3
public static string getHtml(string url, params string [] charSets)//url是要访问的网站地址，charSet是目标网页的编码，如果传入的是null或者""，那就自动分析网页的编码
{
try
{
string charSet = null;
if (charSets.Length == 1) {
charSet = charSets[0];
}
WebClient myWebClient = new WebClient(); //创建WebClient实例myWebClient
// 需要注意的：
//有的网页可能下不下来，有种种原因比如需要cookie,编码问题等等
//这是就要具体问题具体分析比如在头部加入cookie
// webclient.Headers.Add("Cookie", cookie);
//这样可能需要一些重载方法。根据需要写就可以了
//获取或设置用于对向 Internet 资源的请求进行身份验证的网络凭据。
myWebClient.Credentials = CredentialCache.DefaultCredentials;
//如果服务器要验证用户名,密码
//NetworkCredential mycred = new NetworkCredential(struser, strpassword);
//myWebClient.Credentials = mycred;
//从资源下载数据并返回字节数组。（加@是因为网址中间有"/"符号）
byte[] myDataBuffer = myWebClient.DownloadData(url);
string strWebData = Encoding.Default.GetString(myDataBuffer);
//获取网页字符编码描述信息
Match charSetMatch = Regex.Match(strWebData, "<meta([^<]*)charset=([^<]*)\"", RegexOptions.IgnoreCase | RegexOptions.Multiline);
string webCharSet = charSetMatch.Groups[2].Value;
if (charSet == null || charSet == "")
charSet = webCharSet;
if (charSet != null && charSet != "" && Encoding.GetEncoding(charSet) != Encoding.Default)
{
strWebData = Encoding.GetEncoding(charSet).GetString(myDataBuffer);
}
else {
strWebData = Encoding.GetEncoding("utf-8").GetString(myDataBuffer);
}
return strWebData;
}
catch (Exception e) { return ""; }
}
