public enum HttpVerb

    {

        Get,

        Post

    }

    public class HttpHelper

    {

        private string _contentType = "application/x-www-form-urlencoded";

        //private string _contentType = "application/json";

        //private string _contentType = "text/xml";

        private int _timeout = ;

        public string EndPoint { get; set; }

        public HttpVerb Method { get; set; }

        public string ContentType { get { return _contentType; } set { _contentType = value; } }

        public string PostData { get; set; }

        /// <summary>

        /// 默认15000毫秒

        /// </summary>

        public int Timeout { get { return _timeout; } set { _timeout = value; } }

        public HttpHelper(string endpoint)

        {

            EndPoint = endpoint;

            Method = HttpVerb.Get;

            ContentType = _contentType;

            PostData = "{}";

        }

        public string Post(string data)

        {

            var service = new Uri(EndPoint);

            var request = WebRequest.CreateHttp(service);

            request.Method = "POST";

            request.Timeout = Timeout;

            request.KeepAlive = true;

            request.ContentLength = ;

            request.ContentType = ContentType;

            request.Accept = "application/json";

            var bytes = Encoding.UTF8.GetBytes(data);

            request.ContentLength = bytes.Length;

            using (var writeStream = request.GetRequestStream())

            {

                writeStream.Write(bytes, , bytes.Length);

            }

            using (var response = (HttpWebResponse)request.GetResponse())

            {

                var responseValue = string.Empty;

                if (response.StatusCode != HttpStatusCode.OK)

                {

                    var message = String.Format(CultureInfo.CurrentCulture, "Request failed. Received HTTP {0}", response.StatusCode);

                    throw new WebException(message);

                }

                using (var responseStream = response.GetResponseStream())

                {

                    if (responseStream != null)

                        using (var reader = new StreamReader(responseStream))

                        {

                            responseValue = reader.ReadToEnd();

                        }

                }

                return responseValue;

            }

        }

        /// <summary>

        /// Request server

        /// </summary>

        /// <param name="parameters">eg. "?q=1234"</param>

        /// <returns></returns>

        public string Get(string parameters)

        {

            var service = new Uri(EndPoint + parameters);

            var request = WebRequest.CreateHttp(service);

            request.Method = "GET";

            request.Timeout = Timeout;

            request.KeepAlive = true;

            request.ContentLength = ;

            request.ContentType = ContentType;

            using (var response = (HttpWebResponse)request.GetResponse())

            {

                var responseValue = string.Empty;

                if (response.StatusCode != HttpStatusCode.OK)

                {

                    var message = String.Format(CultureInfo.CurrentCulture, "Request failed. Received HTTP {0}", response.StatusCode);

                    throw new WebException(message);

                }

                using (var responseStream = response.GetResponseStream())

                {

                    if (responseStream != null)

                        using (var reader = new StreamReader(responseStream))

                        {

                            responseValue = reader.ReadToEnd();

                        }

                }

                return responseValue;

            }

        }

        /// <summary>

        /// 下载更新二进制文件

        /// </summary>

        /// <param name="parameters">eg. "?q=1234"</param>

        /// <returns></returns>

        public byte[] DownLoad(string parameters)

        {

            var service = new Uri(EndPoint + parameters);

            var request = WebRequest.CreateHttp(service);

            request.Timeout = Timeout;

            request.KeepAlive = true;

            request.Method = Method.ToString().ToUpper(CultureInfo.CurrentCulture);

            request.ContentLength = ;

            request.ContentType = ContentType;

            if (Method == HttpVerb.Post)

            {

                var bytes = Encoding.UTF8.GetBytes(PostData);

                request.ContentLength = bytes.Length;

                using (var writeStream = request.GetRequestStream())

                {

                    writeStream.Write(bytes, , bytes.Length);

                }

            }

            using (var response = (HttpWebResponse)request.GetResponse())

            {

                if (response.StatusCode != HttpStatusCode.OK)

                {

                    var message = String.Format(CultureInfo.CurrentCulture, "Request failed. Received HTTP {0}", response.StatusCode);

                    throw new WebException(message);

                }

                using (var result = new MemoryStream())

                {

                    const int bufferLen = ;

                    var buffer = new byte[bufferLen];

                    using (var responseStream = response.GetResponseStream())

                    {

                        if (responseStream != null)

                        {

                            var len = responseStream.Read(buffer, , bufferLen);

                            while (len > )

                            {

                                result.Write(buffer, , len);

                                len = responseStream.Read(buffer, , bufferLen);

                            }

                        }

                    }

                    return result.ToArray();

                }

            }

        }

    }