programList/ProgrammList/ConfigManager/ConfigManager.cs

using System.Configuration;

namespace ProgrammList.ConfigManager {
    public class ConfigManager {
        public static string GetSetting(string key) {
            return ConfigurationManager.AppSettings[key];
        }

        public static void SetSetting(string key, string value) {
            Configuration configuration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
            configuration.AppSettings.Settings[key].Value = value;
            configuration.Save(ConfigurationSaveMode.Full, true);
            ConfigurationManager.RefreshSection("appSettings");

        }
    }
}