C#怎么实现自动更新本地程序

 　　 if (UpdateSystem(Path.Combine(Application.StartupPath, "Version.txt"), Path.Combine(Application.StartupPath, "u.zip")))
            {
                Application.Exit();
            }

/// <summary>
        /// 读取本地版本请求更新
        /// </summary>
        /// <param name="document">读取的文件信息</param>
        /// <param name="zipPath">返回zip包本地路径</param>
        /// <returns></returns>
        private bool UpdateSystem(string document, string zipPath)
        {
            try
            {
                Dictionary<string, string> postDic = new Dictionary<string, string>();
                //获取文件内的版本号
                if(File.Exists(document))
                {
                    postDic.Add("version", File.ReadAllText(document).Trim());
                }
                else
                {
                    postDic.Add("version", "0");
                }

                string postJson = JsonConvert.SerializeObject(postDic);
                string url = GetAppSettingValue("serverUrl") + "parkClient/parkClientUpdate";
                //返回的json数据
                JObject obj = (JObject)JsonConvert.DeserializeObject(PostData(postJson, url));
                string newVersion = obj["version"].ToString();
                if (!String.IsNullOrWhiteSpace(newVersion))
                {
                    byte[] bytesFile = Convert.FromBase64String(obj["byteArray"].ToString());
                    if (obj["clientMD5"].ToString() == BitConverter.ToString(
                        new System.Security.Cryptography.MD5CryptoServiceProvider().ComputeHash(bytesFile)).Replace("-", ""))
                    {
                        ZipCoverage(bytesFile, zipPath);

                        File.WriteAllText(document, newVersion);
                       
                    }
                }

                return true;
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                return false;
            }
        }

        /// <summary>
        /// 解压zip包覆盖更新
        /// </summary>
        /// <param name="bytes">接受更新包的字节信息</param>
        /// <param name="zpath">覆盖的路径</param>
        private void ZipCoverage(byte[] bytes, string zpath)
        {
            File.WriteAllBytes(zpath, bytes);
            using (ZipArchive archive = ZipFile.OpenRead(zpath))
            {
                string file = null;
                foreach (ZipArchiveEntry entry in archive.Entries)
                {
                    if (!entry.FullName.EndsWith("/"))
                    {
                        file = Path.Combine(Application.StartupPath, entry.FullName);
                        if (File.Exists(file))
                        {
                            File.Delete(file);
                        }
                    }
                }
            }
            ZipFile.ExtractToDirectory(zpath, Application.StartupPath);
           
        }

        /// <summary>
        /// 获取配置文件中的appSettings节中的配置内容
        /// </summary>
        /// <param name="appSettingKey"></param>
        /// <param name="message"></param>
        /// <returns></returns>
        private string GetAppSettingValue(string appSettingKey)
        {
            ExeConfigurationFileMap map = new ExeConfigurationFileMap { ExeConfigFilename = @"TDH.Parking.Client.exe.config" };
            return ConfigurationManager.OpenMappedExeConfiguration(map, ConfigurationUserLevel.None).AppSettings.Settings[appSettingKey].Value;
        }

byte[] bytesFile = Convert.FromBase64String(obj["byteArray"].ToString());