C#

using System;<br />
using System.Collections.Generic;<br />
using System.Text;<br />
using System.Collections.ObjectModel;<br />
using System.ComponentModel.Design;<br />
using System.ComponentModel;<br />
using System.Drawing.Design;<br />
<br />
namespace Test<br />
{<br />
    public abstract class BaseItem<br />
    {<br />
        private string _name;<br />
<br />
        public string Name<br />
        {<br />
            get { return this._name; }<br />
            set { this._name = value; }<br />
        }<br />
    }<br />
<br />
    public class IntItem : BaseItem<br />
    {<br />
        private int _value;<br />
<br />
        public int Value<br />
        {<br />
            get { return this._value; }<br />
            set { this._value = value; }<br />
        }<br />
    }<br />
<br />
    public class StringItem : BaseItem<br />
    {<br />
        private string _value;<br />
<br />
        public string Value<br />
        {<br />
            get { return this._value; }<br />
            set { this._value = value; }<br />
        }<br />
    }<br />
<br />
    public class ItemCollection : Collection<BaseItem><br />
    {<br />
    }<br />
<br />
    public class ItemCollectionEditor : CollectionEditor<br />
    {<br />
        public ItemCollectionEditor(Type type)<br />
            : base(type)<br />
        {<br />
        }<br />
<br />
        protected override Type[] CreateNewItemTypes()<br />
        {<br />
            return new Type[] { typeof(IntItem), typeof(StringItem) };<br />
        }<br />
    }<br />
<br />
    public class ItemCollectionHostControl : System.Windows.Forms.Control<br />
    {<br />
        private ItemCollection _items;<br />
<br />
        public ItemCollectionHostControl()<br />
        {<br />
            this._items = new ItemCollection();<br />
        }<br />
<br />
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Content),<br />
         Editor(typeof(ItemCollectionEditor), typeof(UITypeEditor))]<br />
        public ItemCollection Items<br />
        {<br />
            get { return this._items; }<br />
        }<br />
    }<br />
}