This is how I do strongly typed application settings. Either pass the Dictionary in if provided by the system, or serialize/deserialize to disk as needed.

Settings.cs

using System.Collections.Generic;
using System.Runtime.CompilerServices;

namespace NegativeEddy.Settings
{
    public class ApplicationSettings
    {
        Dictionary<string, object> _settingsBag;

        public void Load()
        {
            // TODO: deserialize file into _settingsBag
        }

        public void Save()
        {
            // TODO: serialize _settingsBag to file
        }

        /// <summary>
        /// Sample int property
        /// </summary>
        public int PreviewCount
        {
            get { return GetSetting(8); }
            set { SetSetting(value); }
        }

        /// <summary>
        /// Sample bool propety
        /// </summary>
        public bool ShowHelpOnLogin
        {
            get { return GetSetting(false); }
            set { SetSetting(value); }
        }

        /// <summary>
        /// Sample string property
        /// </summary>
        public string Token
        {
            get { return GetSetting(string.Empty); }
            set { SetSetting( value); }
        }



        private T GetSetting<T>(T defaultVal, [CallerMemberName] string key = null)
        {
            if (_settingsBag.ContainsKey(key))
            {
                return (T)_settingsBag[key];
            }
            else
            {
                return defaultVal;
            }
        }

        private void SetSetting<T>(T value, [CallerMemberName]string key = null)
        {
            _settingsBag[key] = value;
        }
    }
}