public void TestConvertNonGenericDictionary()
        {
            var e1 = new DictionaryEntry("2", "second");
            var e2 = new KeyValuePair <string, string>(e1.Key.ToString(), e1.Value.ToString());

            var gd = new Dictionary <string, string>();

            gd.Add("a", "first");
            gd.Add("b", "second");

            var ht = new Hashtable();

            ht.Add("a", "first");
            ht.Add("b", "second");

            ht.AsQueryable();   // here
            var result = ht.Cast <KeyValuePair <string, string> >();

            foreach (var item in result)
            {
                Trace.WriteLine(item);
            }
        }