C# gzip 解压 有关问题

C# gzip 解压 问题
最近公司 要做一个接口，不过对方放回的 是通过gzip 加压过的，现在我只能得到乱码的字符串，请问如果讲 gzip 解压 成 原来的 字符串
[解决办法]
http://stackoverflow.com/questions/1581694/gzipstream-and-decompression
[解决办法]

if (HttpWResp.ContentEncoding.ToLower().Contains("gzip"))
            {
                using (GZipStream stream = new GZipStream(HttpWResp.GetResponseStream(), CompressionMode.Decompress))
                {
                    using (reader = new StreamReader(stream, System.Text.Encoding.GetEncoding("gb2312")))
                    {
                        result = reader.ReadToEnd();
                        //return HttpUtility.HtmlDecode(result);
                    }
                }
            }
            else
            {
                Stream myStream = HttpWResp.GetResponseStream();
                using (reader = new StreamReader(myStream, System.Text.Encoding.GetEncoding("gb2312")))
                {
                    result = reader.ReadToEnd();
                }
            }