ControlTagExtentionsWinForms

    public static class ControlTagExtentions {

        public static T GetTagItem<T>(this Control c,string key) {
            Dictionary<string,object> tagDict = null;

            if(c.Tag == null) {
                tagDict = new Dictionary<string,object>();
                c.Tag = tagDict;
            }
            else {
                tagDict = c.Tag as Dictionary<string,object>;
                if(tagDict == null)
                    return default(T);
            }
            if(!tagDict.ContainsKey(key))
                return default(T);

            return (T)tagDict[key];
        }

        public static void SetTagItem(this Control c,string key,object value) {
            Dictionary<string,object> tagDict = null;
            if(c.Tag == null) {
                tagDict = new Dictionary<string,object>();
                c.Tag = tagDict;
            }
            else {
                tagDict = c.Tag as Dictionary<string,object>;
                if(tagDict == null) {
                    tagDict = new Dictionary<string,object>();
                    c.Tag = tagDict;
                }
            }
            tagDict[key] = value;
        }
    }