public interface IProperties
    {
        /// <summary>
        /// Gets or sets the id.
        /// </summary>
        /// <value>The id (must be unique).</value>
        string id { get; set;}
 
        /// <summary>
        /// Gets or sets the einText.
        /// </summary>
        /// <value>The einText.</value>
        string einText { get; set;}
    }

    class ButtonWithProperties : Button, IProperties
    {
        private Properties _properties = new Properties();
 
        public string id
        {
            get { return _properties.id; }
            set { _properties.id = value; }
        }
 
        public string einText
        {
            get { return _properties.einText; }
            set { _properties.einText = value; }
        }
    }

Those people who think they know everything are a great annoyance to those of us who do - Isaac Asimov