using System;using System.Collections.Generic;using System.Text;using System.Collections; namespace HashtableExample{    class Program    {        static void Main(string[] args)        {            //创建一个新的hash表.表示键/值对的集合，这些键/值对根据键的哈希代码进行组织。            Hashtable openWith = new Hashtable();             //添加一些元素            openWith.Add("txt", "notepad.exe");            openWith.Add("bmp", "paint.exe");            openWith.Add("dib", "paint.exe");            openWith.Add("rtf", "wordpad.exe");             //如果新添加的元素已经在表中，则抛出异常            try            {                openWith.Add("txt", "winword.exe");            }            catch            {                Console.WriteLine("带有Key是 \"txt\" 的元素已经存在.");            }             Console.WriteLine("For key = \"rtf\", value = {0}.", openWith["rtf"]); //---------------------------------------------------------------------------------------------------             //openWith["rtf"] = "winword.exe";           openWith["rtf"] = "测试1";            Console.WriteLine("For key = \"rtf\", value = {0}.", openWith["rtf"]); //---------------------------------------------------------------------------------------------------            openWith["doc"] = "winword.exe";             //如果寻找的不在表中，则抛出异常            try            {                Console.WriteLine("For key = \"tif\", value = {0}.", openWith["tif"]);            }            catch            {                Console.WriteLine("Key = \"tif\" is not found.");            }             // 在插入之前，ContainsKey用来测试keys            if (!openWith.ContainsKey("ht"))            {                openWith.Add("ht", "hypertrm.exe");                Console.WriteLine("8888888888888Value added for key = \"ht\": {0}", openWith["ht"]);            }             // foreach枚举hash表的元素            Console.WriteLine();            foreach (DictionaryEntry de in openWith)            {                Console.WriteLine("555555555Key = {0}, Value = {1}", de.Key, de.Value);            }             // Values属性获取            ICollection valueColl = openWith.Values;             // ValueCollection的值输出            Console.WriteLine();            foreach (string s in valueColl)            {                Console.WriteLine("66666666Value = {0}", s);            }             ICollection keyColl = openWith.Keys;             // ValueCollection的值输出            Console.WriteLine();            foreach (string s in keyColl)            {                Console.WriteLine("2222222222222Key = {0}", s);            }             // Remove方法删除key/value.            Console.WriteLine("\nRemove(\"doc\")");             Console.WriteLine("删除前 "+openWith["doc"]);            openWith.Remove("doc");             if (!openWith.ContainsKey("doc"))            {                Console.WriteLine("Key \"doc\" is not found.");            }             Console.Read();        }    }}

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