有時使用HttpWebRequest對象會出現錯誤，總結有三種： 
1、System.Net.WebException: 服務器提交了協議沖突. Section=ResponseStatusLine 
2、System.Net.WebException: 基礎連接已經關閉: 連接被意外關閉。 
3、System.Net.ProtocolViolationException: 無法發送具有此謂詞類型的內容正文。 
使用TcpClient對象搞定： 

復制代碼代碼如下:

private string GetHTMLTCP(string URL) 
{ 
string strHTML = "";//用來保存獲得的HTML代碼 
TcpClient clientSocket = new TcpClient(); 
Uri URI = new Uri(URL); 
clientSocket.Connect(URI.Host, URI.Port); 
StringBuilder RequestHeaders = new StringBuilder();//用來保存HTML協議頭部信息 
RequestHeaders.AppendFormat("{0} {1} HTTP/1.1\r\n", "GET", URI.PathAndQuery); 
RequestHeaders.AppendFormat("Connection:close\r\n"); 
RequestHeaders.AppendFormat("Host:{0}\r\n", URI.Host); 
RequestHeaders.AppendFormat("Accept:*/*\r\n"); 
RequestHeaders.AppendFormat("Accept-Language:zh-cn\r\n"); 
RequestHeaders.AppendFormat("User-Agent:Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)\r\n\r\n"); 
Encoding encoding = Encoding.Default; 
byte[] request = encoding.GetBytes(RequestHeaders.ToString()); 
clientSocket.Client.Send(request); 
//獲取要保存的網絡流 
Stream readStream = clientSocket.GetStream(); 
StreamReader sr = new StreamReader(readStream, Encoding.Default); 
strHTML = sr.ReadToEnd(); 
readStream.Close(); 
clientSocket.Close(); 
return strHTML; 
} 

使用 HttpWebRequest請求頁面 

復制代碼代碼如下:

/// 
/// 獲取html源碼 
/// 
/// 
/// 
/// 
static string GetHTML(string url, string param) 
{ 
try 
{ 
Uri uri = new Uri(url); 
HttpWebRequest myReq = (HttpWebRequest)WebRequest.Create(uri); 
myReq.Headers.Add("Accept-Encoding", "gzip,deflate");//sdch 
byte[] byData = Encoding.Default.GetBytes(param); 
myReq.Method = "post"; 
myReq.ContentLength = byData.Length; 
Stream reqStrem = myReq.GetRequestStream(); 
reqStrem.Write(byData, 0, byData.Length); 
reqStrem.Close(); 
HttpWebResponse result = (HttpWebResponse)myReq.GetResponse(); 
Stream recStream = result.GetResponseStream(); 
//如果是Gzip方式則需要解壓 
recStream = new GZipStream(recStream, CompressionMode.Decompress); 
StreamReader redStream = new StreamReader(recStream, System.Text.Encoding.Default); 
string strHTML = redStream.ReadToEnd(); 
redStream.Close(); 
recStream.Close(); 
result.Close(); 
return strHTML; 
} 
catch (Exception) 
{ 
return ""; 
} 
}