Change in application configuration without application restart

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;