c#发送http请求get post

using System;using System.IO;using System.Net;        public 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";   //在http请求中附加cookie，服务端可以通过$_COOKIE获取            request.Headers["Cookie"] = "Url=http://dotnet.aspx.cc; UserInfo=UserName=" + System.Web.HttpUtility.UrlEncode("孟宪会") + ";UserId=net_lover";             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;        }