方法一:

using System.Text;
using System.Net;
private string getHtml(string url)
{
WebClient myWebClient = new WebClient();
byte[] myDataBuffer = myWebClient.DownloadData (url);
return Encoding.Default.GetString(myDataBuffer);
}

方法二:

public string getHttp(string HttpUrl,string RefererUrl)
{
string html = "";
try
{
MSXML2.XMLHTTP Http = new MSXML2.XMLHTTPClass();
xmlhttp.open("GET", Url, false, null, null);
Http.open("GET",HttpUrl,false,null,null);
Http.setRequestHeader("Referer",RefererUrl);
//Http.setRequestHeader("Referer",RefererUrl);
Http.setRequestHeader("Content-Type", "text/html;charset=gb2312");
Http.send("");
html = Encoding.Default.GetString((byte[])Http.responseBody);
Http = null;
}
catch
{

}
return html;
}

public bool getweb(string strURL,out string buf)
  {
   buf="";
   try
   {
    //Uri url=new Uri(strURL,false);
    HttpWebRequest request;
    request = (HttpWebRequest)WebRequest.Create(strURL);
    request.Method="POST"; //Post请求方式
    request.ContentType="application/x-www-form-urlencoded"; //内容类型
    string paraUrlCoded = System.Web.HttpUtility.UrlEncode(""); //参数经过URL编码
    byte[] payload;
    payload = System.Text.Encoding.GetEncoding("GB2312").GetBytes(paraUrlCoded); //将URL编码后的字符串转化为字节
    request.ContentLength = payload.Length; //设置请求的ContentLength
    Stream writer = request.GetRequestStream(); //获得请求流
    writer.Write(payload,0,payload.Length); //将请求参数写入流
    writer.Close(); //关闭请求流
    HttpWebResponse response;
    response = (HttpWebResponse)request.GetResponse(); //获得响应流
    Stream s;
    s = response.GetResponseStream();
    StreamReader objReader = new StreamReader(s,System.Text.Encoding.GetEncoding("GB2312"));
    string HTML = "";
    string sLine ="";
    int i = 0;
    while (sLine!=null)
    {
     i++;
     sLine = objReader.ReadLine();
     if (sLine!=null)
      HTML += sLine;
    }
    //HTML = HTML.Replace("&lt;","<");
    //HTML = HTML.Replace("&gt;",">");
    buf=HTML;
    return true;
   }
   catch (Exception x)
   {  
    buf=x.Message.ToString();
    return false;   
   }
  }
 
带Cookie：
CookieContainer cc = new CookieContainer();
public bool getweb(string strURL,out string buf)
  {
   buf="";
   try
   {
    HttpWebRequest request;
    request = (HttpWebRequest)WebRequest.Create(strURL);
    request.Method="POST"; //Post请求方式
    request.ContentType="text/html;charset=gb2312"; //内容类型
    string paraUrlCoded = System.Web.HttpUtility.UrlEncode(""); //参数经过URL编码
    byte[] payload;
    payload = System.Text.Encoding.GetEncoding("GB2312").GetBytes(paraUrlCoded); //将URL编码后的字符串转化为字节
    request.ContentLength = payload.Length; //设置请求的ContentLength
    Stream writer = request.GetRequestStream(); //获得请求流
    writer.Write(payload,0,payload.Length); //将请求参数写入流
    writer.Close(); //关闭请求流
    HttpWebResponse response;
    response = (HttpWebResponse)request.GetResponse(); //获得响应流
    Stream s;
    s = response.GetResponseStream();
    StreamReader objReader = new StreamReader(s,System.Text.Encoding.GetEncoding("GB2312"));
    string HTML = "";
    string sLine ="";
    int i = 0;
    while (sLine!=null)
    {
     i++;
     sLine = objReader.ReadLine();
     if (sLine!=null)
      HTML += sLine;
    }

    buf=HTML;
    return true;
   }
   catch (Exception x)
   {  
    buf=x.Message.ToString();
    return false;   
   }
  }
  public bool getweb(string strURL,out string buf,string postData)
  {
   buf="";
   try
   {  
   
    ASCIIEncoding encoding = new ASCIIEncoding();
    byte[] data = encoding.GetBytes(postData);
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(strURL);
    request.Method = "POST";
    request.ContentType = "application/x-www-form-urlencoded";
    request.ContentLength = data.Length;
    Stream newStream = request.GetRequestStream();
    newStream.Write(data, 0, data.Length);
    newStream.Close();
                  
    request.CookieContainer = cc;
                  
    HttpWebResponse response = (HttpWebResponse)request.GetResponse();
    cc.Add(response.Cookies);
    Stream stream = response.GetResponseStream();
    string sHtml = new StreamReader(stream, System.Text.Encoding.Default).ReadToEnd();
    buf=sHtml;
    return true;
   }
   catch (Exception x)
   {  
    buf=x.Message.ToString();
    return false;   
   }
  }

private   string   getWebresourceFile1(string   url)
    {
  
WebClient   myWebClient   =   new   WebClient();   
byte[]   myDataBuffer   =   myWebClient.DownloadData(url);
string   SourceCode   =   Encoding.Default.GetString(myDataBuffer);
saveSourceCode(SourceCode);
                  return   SourceCode;
      }

方法2
private   string   getWebresourceFile2(string   url)
    {
HttpWebRequest   request=(HttpWebRequest)WebRequest.Create(url); 
HttpWebResponse   response=(HttpWebResponse)request.GetResponse(); 
                  request.Method   =   "GET ";       
Stream   receiveStream=response.GetResponseStream();
StreamReader   readStream=new   StreamReader(receiveStream,Encoding.Default);
string   SourceCode=readStream.ReadToEnd();   
saveSourceCode(SourceCode);
response.Close();     
readStream.Close();
return   SourceCode;

      }
方法3
private   string   getWebresourceFile3(string   url)
      {
WebClient   wc   =   new   WebClient();
wc.Credentials   =   CredentialCache.DefaultCredentials;
Byte[]   pageData   =   wc.DownloadData(url);
string   SourceCode   =   Encoding.Default.GetString(pageData);
saveSourceCode(SourceCode);
wc.Dispose(); 
return   SourceCode;
      }

方法4
private   string   getWebresourceFile4(string   url)
    {
WebClient   wc   =   new   WebClient();
wc.Credentials   =   CredentialCache.DefaultCredentials;
Stream   resStream   =   wc.OpenRead(url);
StreamReader   sr   =   new   StreamReader(resStream,System.Text.Encoding.Default);