Read Config File from a different location

ExeConfigurationFileMap cf =
                new ExeConfigurationFileMap() { ExeConfigFilename = "C:\\app.config" };


            Configuration configFile = ConfigurationManager.OpenMappedExeConfiguration(cf, ConfigurationUserLevel.None);


This by default provides KeyValuePair when you attempt to read the settings. To return KeyValuePair as NameValuePair, Use as below. 




            ExeConfigurationFileMap cf =
                new ExeConfigurationFileMap() { ExeConfigFilename = "C:\\app.config" };


            Configuration confFile = ConfigurationManager.OpenMappedExeConfiguration(cf, ConfigurationUserLevel.None);
                       NameValueCollection _collsettings = new NameValueCollection();
            foreach (string key in confFile.AppSettings.Settings.AllKeys)
            {
                 _collsettings.Add(confFile.AppSettings.Settings[key].Key, confFile.AppSettings.Settings[key].Value);
            }


If you are reading machine config file, make use of Suitable class instead of Execonfigurationfilemap.