Dictionary<string, string> dic = new Dictionary<string, string>();

            dic.Add("a", "北京");

            dic.Add("c", "上海");

            dic.Add("b", "广州");

            dic.Add("d", "深圳");

            foreach (KeyValuePair<string, string> d in dic)

            {

                Console.WriteLine(d.Key + "  " + d.Value);

            }

            foreach (var itm in dic)

            {

                Console.WriteLine(itm.Key + "  " + itm.Value);

            }

            foreach (string s in dic.Keys)

            {

                Console.WriteLine(s + "  " + dic[s]);

            }

            foreach (string s in dic.Values)

            {

                Console.WriteLine(s);

            }

            字典排序：List<KeyValuePair<string,string>> list = dic.OrderBy(r => r.Key).ToList<KeyValuePair<string, string>>();
　　　　　　　//dic =dic.OrderByDescending(r => r.Key).ToDictionary(r => r.Key, r => r.Value);

            foreach (KeyValuePair<string, string> kv in list)

            {

                Console.WriteLine(kv.Key + "  " + kv.Value);

            }