public partial class Demo : System.Web.UI.UserControl, umbraco.editorControls.userControlGrapper.IUsercontrolDataEditor  
    {
        [DataEditorSetting("testing", description="using DataEditorSettings on usercontrol")]
        public string Testing { get; set; }

        public string umbracoValue;

        protected void Page_Load(object sender, EventArgs e)
        {
            if (Page.IsPostBack)
            {

            }
            else
            {
                Literal1.Text = Testing;
            }
        }

        public object value
        {
            get
            {
                return umbracoValue;
            }
            set
            {
                umbracoValue = value.ToString();
            }
        }
    }

http://umbraco.org

Umbraco Juno, usercontrol wrapper also support data editor settings = custom settings on on your usercontrol datatype

C#