Extended CheckboxList property

CheckboxList - Dojo widget

define([
    "dojo/_base/declare",
     "dojo/_base/array",
     "epi-cms/contentediting/editors/CheckBoxListEditor"
], function (
    declare,
    array,
    _CheckBoxListEditor
) {

    return declare("alloy.editors.extendedCheckBoxListEditor", _CheckBoxListEditor, {

        buildRendering: function () {
            this.inherited(arguments);
            if (this.readOnly) {
                return;
            }
            array.forEach(this._checkboxes, this._setCheckboxEnabled, this);
        },

        _setCheckboxEnabled: function(checkbox) {
            var selectedItem = array.filter(this.selections, function (item) {
                return item.value == checkbox.value;
            }, this)[0];
            checkbox.set("readOnly", selectedItem.enabled === false);
        }
    });
});

CheckboxList - Extended SelectItem

public class ExtendedSelectItem : SelectItem
{
    public bool Enabled { get; set; }
}

CheckboxList - page model

public class ProductPage : StandardPage
{
  //...
  [ClientEditor(ClientEditingClass = "alloy.editors.extendedCheckBoxListEditor", SelectionFactoryType = typeof(ContinentSelectionFactory))]
  public virtual string Continents { get; set; }
  //...
}

CheckboxList - SelectionFactory

using System.Collections.Generic;
using EPiServer.Shell.ObjectEditing;

namespace EpiServerThumbnail.Business.EditorDescriptors
{
    public class ContinentSelectionFactory: ISelectionFactory
    {
        public IEnumerable GetSelections(ExtendedMetadata metadata)
        {
            var items = new[]
            {
                new ExtendedSelectItem
                {
                    Enabled = false,
                    Text = "Australia",
                    Value = "Au"
                },
                new ExtendedSelectItem
                {
                    Enabled = true,
                    Text = "Africa",
                    Value = "Af"
                },
                new ExtendedSelectItem
                {
                    Enabled = true,
                    Text = "Asia",
                    Value = "As"
                },
                new ExtendedSelectItem
                {
                    Enabled = true,
                    Text = "Europe",
                    Value = "Eu",
                },
                new ExtendedSelectItem
                {
                    Enabled = true,
                    Text = "North America",
                    Value = "NoAm"
                },
                new ExtendedSelectItem
                {
                    Enabled = false,
                    Text = "South America",
                    Value = "SoAm"
                }
            };
            return items;
        }
    }    
}