修改config配置文件

        public static void SetValue(string key, string value)
        {
            string file = System.Windows.Forms.Application.ExecutablePath;

            Configuration configuration = ConfigurationManager.OpenMappedExeConfiguration(new ExeConfigurationFileMap
            {
                ExeConfigFilename = file + ".config"
            }, ConfigurationUserLevel.None);
            configuration.AppSettings.Settings[key].Value = value;
            configuration.Save();
        }

 配置文件刷新

ConfigurationManager.RefreshSection("appSettings");