Change in application configuration without application restart

Question

I have following issue: I'm introducing new feature into application (run as Windows Service) and I would like to have that new feature controlled (on/off) using some kind of configuration file entry (myKey). I can store config entry in app.config but if I want to change it from on->off or otherwise it would require to restart Windows Service, and I want to avoid it. I want my application to run and pick up changes in configuration.

The question is: is there a build in mechanism in .NET that addresses that problem ? I guess I could create my own config file, then use FileSystemWatcher etc... But perhaps .NET allows to use external config files and will reload value ??

ConfigurationManager.AppSettings["myKey"]

Thanks, Pawel

EDIT 1: Thanks for replies. However I wrote following snippet and it doesn't work (I tried creating appSettingSection in both places: before and inside loop):

static void Main(string[] args)
{
    Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
    // AppSettingsSection appSettingSection = (AppSettingsSection)config.GetSection("appSettings");
    for (int i = 0; i < 10; i++)
    {
        ConfigurationManager.RefreshSection("appSettings");
        AppSettingsSection appSettingSection = (AppSettingsSection)config.GetSection("appSettings");
        string myConfigData = appSettingSection.Settings["myConfigData"].Value; // still the same value, doesn't get updated
        Console.WriteLine();
        Console.WriteLine("Using GetSection(string).");
        Console.WriteLine("AppSettings section:");
        Console.WriteLine(
          appSettingSection.SectionInformation.GetRawXml()); // also XML is still the same
        Console.ReadLine();
    }
}

I manually edit config file when application stops on Console.ReadLine().

Answer 1

Once the original app.config file is loaded, it's values are cached so as you know, you'll have to restart the app. The way around this is to create a new config object and read the keys manually like this:

var appConfig = ConfigurationManager.OpenExeConfiguration(Assembly.GetExecutingAssembly().Location);
string myConfigData = appConfig.AppSettings.Settings["myConfigData"].Value;