static void Main(string[] args)
        {
            // 實例化一個哈希表
            Hashtable ht = new Hashtable();

            /**********基本操作**********/
            // 添加一個key/value鍵值對
            ht.Add("user","admin");
            ht.Add("name", "admin");

            // 移除鍵值對
            //ht.Remove("user");

            // 移除所有元素
            //ht.Clear();

            // 判斷key是否已存在
            Console.WriteLine(ht.Contains("user"));

            // 輸出值
            Console.WriteLine(ht["user"]);

            /**********遍歷操作**********/
            foreach (DictionaryEntry de in ht)
            {
                Console.WriteLine("Key: {0}, Value: {1}", de.Key, de.Value);
            }

            Console.WriteLine("");

            /**********排序操作**********/
            ArrayList keys = new ArrayList(ht.Keys);
            // 排序, a->z
            keys.Sort();
            Console.WriteLine("正序");
            foreach (string key in keys)
            {
                Console.WriteLine(key + ": {0}", ht[key]);
            }

            Console.WriteLine("");

            // 排序, z->a
            keys.Reverse();
            Console.WriteLine("倒序");
            foreach (string key in keys)
            {
                Console.WriteLine(key + ": {0}", ht[key]);
            }

            Console.ReadLine();
        }