求C#中的HttpWebRequest 例子？

Question

我今天发现HttpWebRequest 可以用自动登陆网站 什么的
我不怎么用 请求各位给我几个例子 让我开悟开悟！3Q3Q

Answer 1

        /// <summary>
        /// 通过POST方式发送数据到web页面
        /// </summary>
        /// <param name="Url">url</param>
        /// <param name="postDataStr">Post数据</param>
        /// <param name="cookie">Cookie容器</param>
        /// <returns>获取的html页面字符串</returns>
        public string SendDataByPost(string Url, string postDataStr, CookieContainer cookie)
        {
            StringBuilder retString = new StringBuilder("");
            HttpWebRequest request;
            string siteencoding = m_spider.GetEncoding();
            try
            {
                request = (HttpWebRequest)WebRequest.Create(Url);
                string line = "";
                if (cookie.Count != 0)
                {
                    request.CookieContainer = cookie;
                }                if (postDataStr != "")
                {
                    // 当post数据不为空时，明确采用post方法，取得返回数据
                    request.Method = "POST";
                    request.ContentType = "application/x-www-form-urlencoded";
                    request.ContentLength = Encoding.GetEncoding(siteencoding).GetBytes(postDataStr).Length;
                    Stream myRequestStream = request.GetRequestStream();                    StreamWriter myStreamWriter = new StreamWriter(myRequestStream, Encoding.GetEncoding(siteencoding));
                    myStreamWriter.Write(postDataStr);
                    myStreamWriter.Flush();
                    myStreamWriter.Close();
                }                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                Stream myResponseStream = response.GetResponseStream();
                if (!response.ContentType.ToLower().StartsWith("text/"))
                {
//                    SaveBinaryFile(response);
                    return null;
                }
                StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding(siteencoding));
                while ((line = myStreamReader.ReadLine()) != null)
                {
                    retString.AppendLine(line);
                }                myStreamReader.Close();
                myResponseStream.Close();
            }
            catch (WebException e)
            {
                Console.WriteLine(e.Message);
                Stream se = e.Response.GetResponseStream();
                StreamReader ss = new StreamReader(se, Encoding.GetEncoding(siteencoding));
                string sss = ss.ReadToEnd();
            }            return retString.ToString();
        }