C#

using System.ComponentModel;
using System.Windows.Forms.Design;

namespace YourNameSpace
{
    public class TestControlDesigner : ParentControlDesigner
    {
        public override void Initialize(IComponent component)
        {
            base.Initialize(component);

            if (Control is InheritedPanel)
                EnableDesignMode((InheritedPanel) Control, Control.Name);
            else if (Control is InheritedPanelHost) EnableDesignMode((InheritedPanelHost) Control, Control.Name);
        }
    }
}

using System.ComponentModel;
using System.Windows.Forms;

namespace YourNameSpace
{
    [Designer(typeof(TestControlDesigner))]
    public partial class InheritedPanel : UserControl
    {
        public InheritedPanel()
        {
            InitializeComponent();
        }
    }
}

using System.ComponentModel;
using System.Windows.Forms;

namespace YourNameSpace
{
    [Designer(typeof(TestControlDesigner))]
    public partial class PanelBase : UserControl
    {
        public PanelBase()
        {
            InitializeComponent();
        }

        [Category("Appearance")]
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
        public TreeView TV { get; private set; }

        [Category("Appearance")]
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
        public Panel TopPanel { get; private set; }

        [Category("Appearance")]
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
        public Panel LowerPanel { get; private set; }

        public void setPanelLabel(string s)
        {
            label1.Text = s;
        }

        private void PanelBase_Load(object sender, EventArgs e)
        {
            // set TV, TopPanel, LowerPanel, Properties to actual Controls
        }
    }
}

Quote:

a custom TabControl which loads custom TabPages

            string strConnect = "my connection string";
            string json = Newtonsoft.Json.JsonConvert.SerializeObject(strConnect);
...
            string readback = Newtonsoft.Json.JsonConvert.DeserializeObject<string>(json);

List<Setting> readback = Newtonsoft.Json.JsonConvert.DeserializeObject<List<Setting>>(json);

using System;
using System.Collections.Generic;
using System.Web.Script.Serialization;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            var list = new List<Person>();
            list.Add(new Person() { Name = "Dude", Age = 21 });
            list.Add(new Person() { Name = "Chap", Age = 28 });

            var json = new JavaScriptSerializer();
            var result = json.Serialize(list);
            var listFromJson = json.Deserialize(result, typeof(List<Person>)) as List<Person>;
        }
    }

    class Person
    {
        public string Name { get; set; }
        public int Age { get; set; }
    }
}

{
  "Settings": {
    "DbConnection": {
      "Connection": "mongodb://admin:Password@localhost",
      "Database": "database"
    },
    "SmtpConnection": {
      "Server": "smtp.gmail.com",
      "User": "emailAddress",
      "Pass": "password",
      "Port": "587",
      "SSL": "True"
    }
  }
}

public class Settings
    {
        public MongoDbConfig DbConnection { get; set; }
        public SmtpConfig SmtpConnection { get; set; }
    }

    public class MongoDbConfig
    {
        public string Connection { get; set; }
        public string Database { get; set; }
    }

    public class SmtpConfig
    {
        public string Server { get; set; }
        public string User { get; set; }
        public string Pass { get; set; }
        public int Port { get; set; }
        public bool SSL { get; set; }
    }

public static void GetSettings()
{
    var appPath = Path.Combine(Application.StartupPath, "appSettings.json");
    var jsonText = File.ReadAllText(appPath);
    var settings = JsonConvert.DeserializeObject<Settings>(jsonText);
    Console.Write(appPath);
}

jsonText = "{\r\n  \"Settings\": {\r\n    \"DbConnection\": {\r\n      \"Connection\": \"mongodb://admin:Password@localhost\",\r\n      \"Database\": \"wirelessDb\"\r\n    },\r\n    \"SmtpConnection\": {\r\n      \"Server\": \"smtp.gmail.com\",\r\n

public class DbConnection
{
    public string Connection { get; set; }
    public string Database { get; set; }
}

public class SmtpConnection
{
    public string Server { get; set; }
    public string User { get; set; }
    public string Pass { get; set; }
    public string Port { get; set; }
    public string SSL { get; set; }
}

public class Settings
{
    public DbConnection DbConnection { get; set; }
    public SmtpConnection SmtpConnection { get; set; }
}

public class RootObject
{
    public Settings Settings { get; set; }
}

JavaScriptSerializer oJS = new JavaScriptSerializer();
RootObject oRootObject = new RootObject();
oRootObject = oJS.Deserialize<RootObject>(jsonText);

public static IEnumerable<int> ExtractBits(int value)
{
    int bit = 1;
    while (bit != 0)
    {
        if ((value & bit) == bit) yield return bit;
        bit <<= 1;
    }
}

public class MyUserControl: UserControl
   {
   ...
   public string FilePath { get; set; }
   ...
   }