C#模拟http 发送post或get请求

private string HttpPost(string Url, 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 = new StreamWriter(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 = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));            string retString = myStreamReader.ReadToEnd();            myStreamReader.Close();            myResponseStream.Close();             return retString;        }         public string HttpGet(string Url, string postDataStr)        {            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 = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));            string retString = myStreamReader.ReadToEnd();            myStreamReader.Close();            myResponseStream.Close();             return retString;        }

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