获取指定文件AppSettings

       // 文件路径
        private static string  ConfigPath = AppDomain.CurrentDomain.BaseDirectory + @"\XXX.config";
        private static AppSettingsSection _sviewFrameSetting;
        public static string OnlineViewService = GetAppSettings("OnlineViewService");

        /// <summary>
        /// 获取指定文件AppSettings
        /// </summary>
        private static void LoadAppSetting()
        {
            ExeConfigurationFileMap map = new ExeConfigurationFileMap();
            map.ExeConfigFilename = ConfigPath ;
            Configuration _sviewFrameConfiguration = ConfigurationManager.OpenMappedExeConfiguration(map,
                     ConfigurationUserLevel.None);
            //如果配置文件中不包括appSettings节,则抛出异常.
            if (_sviewFrameConfiguration.Sections["appSettings"] != null)
            {
                _sviewFrameSetting = _sviewFrameConfiguration.AppSettings;
            }
        }

        /// <summary>
        /// 获取配置信息
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        private static string GetAppSettings(string key)
        {
            if (_sviewFrameSetting == null)
            {
                LoadAppSetting();
            }

            return _sviewFrameSetting.Settings[key].Value;
        }