AjaxCheckboxList

This control is like the AjaxDropdown, has all the features, except you select many instead of one value.
Example:

<o:AjaxCheckboxList runat="server" ID="SimpleCategories" Url="~/svc/aja.svc/CategoriesCheckboxList"></o:AjaxCheckboxList>

[WebGet]
[OperationContract]
public IEnumerable<SelectListItem> CategoriesCheckboxList(string v)
{
    var keys = v.GetIntArray();
    return Categories
        .Select(o => new SelectListItem
        {
            Value = o.Id,
            Text = o.Name,
            Selected = keys.Contains(o.Id)
        });
}

getting and setting the value of the AjaxCheckboxList is done the same way as for the MultiLookup