GetEnumerator方法应用---获取Hashtable所有键值及清除所有缓存

获取所有Hashtable 键值只需用到GetEnumerator()方法。
如下：
 Hashtable a = new Hashtable();
            a["a"] = "fda";
            a["a1"] = "fda";
            a["a2"] = "fda";
            IDictionaryEnumerator CacheEnum1 = a.GetEnumerator();
            string str= string.Empty;
            while (CacheEnum1.MoveNext())
            {
                str+= "," + CacheEnum1.Entry.Key.ToString();
            }

即str=,a2,a1,a
清除所有缓存
IDictionaryEnumerator CacheEnum = Cache.GetEnumerator();
   while (CacheEnum.MoveNext())
   {
       Cache.Remove(CacheEnum.Entry.Key.ToString());
   }