private string HttpPost( stringUrl,string postDataStr)

{

HttpWebRequest  request = (HttpWebRequest)WebRequest.Create(Url);

request.Method ="POST";

request.ContentType ="application/x-www-form-urlencoded";

request.ContentLength = Encoding.UTF8.GetByteCount(postDataStr);

request.CookieContainer = cookie;

Stream myRequestStream = request.GetRequestStream();

StreamWriter myStreamWriter =newStreamWriter(myRequestStream, Encoding.GetEncoding("gb2312"));

myStreamWriter.Write(postDataStr);

myStreamWriter.Close();

HttpWebResponse response = (HttpWebResponse)request.GetResponse();

response.Cookies = cookie.GetCookies(response.ResponseUri);

Stream myResponseStream = response.GetResponseStream();

StreamReader myStreamReader =newStreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));

stringretString = myStreamReader.ReadToEnd();

myStreamReader.Close();

myResponseStream.Close();

returnretString;

}

publicstringHttpGet(stringUrl,stringpostDataStr)

{

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url + (postDataStr ==""?"":"?") + postDataStr);

request.Method ="GET";

request.ContentType ="text/html;charset=UTF-8";

HttpWebResponse response = (HttpWebResponse)request.GetResponse();

Stream myResponseStream = response.GetResponseStream();

StreamReader myStreamReader =newStreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));

stringretString = myStreamReader.ReadToEnd();

myStreamReader.Close();

myResponseStream.Close();

returnretString;

}

在post的时候有时也用的到cookie，像登录163发邮件时候就需要发送cookie，所以在外部一个cookie属性随时保存 CookieContainer cookie = new CookieContainer();

！注意：有时候请求会重定向，但我们就需要从重定向url获取东西，像QQ登录成功后获取sid，但上面的会自动根据重定向地址跳转。我们可以用:

request.AllowAutoRedirect = false;设置重定向禁用，你就可以从headers的Location属性中获取重定向地址