private string HttpPost(string url, Dictionary<string, string> vals) {
                string param = "";
                foreach (string k in vals.Keys) {
                    string key = k.Replace("#", "");
                    param += String.Format("{0}={1}&", key, vals[k]);
                }
                byte[] data = Encoding.ASCII.GetBytes(param);

                // リクエストの作成
                System.Net.HttpWebRequest req = (System.Net.HttpWebRequest)System.Net.WebRequest.Create(url);
                req.Method = "POST";
                req.ContentType = "application/x-www-form-urlencoded";
                req.ContentLength = data.Length;
                req.CookieContainer = _cookieContainer;

                // ポスト・データの書き込み
                System.IO.Stream reqStream = req.GetRequestStream();
                reqStream.Write(data, 0, data.Length);
                reqStream.Close();

                System.Net.WebResponse res = req.GetResponse();

                // レスポンスの読み取り
                System.IO.Stream resStream = res.GetResponseStream();
                System.IO.StreamReader sr = new System.IO.StreamReader(resStream, encoder);
                string result = sr.ReadToEnd();
                sr.Close();
                resStream.Close();

                return result;
            }

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