代码如下：

public class DictionaryApplication
    {
        public Dictionary<int, string> dic = new Dictionary<int, string>();
        public delegate void ergodic();
        public DictionaryApplication()
        {
            if (dic == null || dic.Count == 0)
            {
                dic.Add(1, "曹操");
                dic.Add(3, "曹彰");
                dic.Add(6, "曹昂");
                dic.Add(7, "曹洪");
                dic.Add(4, "曹真");
                dic.Add(8, "曹丕");
                dic.Add(5, "曹仁");
                dic.Add(9, "曹叡");
                dic.Add(2, "曹植");
            }
            Run(ForEach);
            Run(ForEachKey);
            Run(ForEachValue);
            Run(ForArray);
        }

        public void Run(ergodic _ergodic)
        {
            _ergodic.Invoke();
        }

        /// <summary>
        /// 
        /// </summary>
        public void ForEach()
        {
            Console.WriteLine("\r\n[----------ForEach开始-----------\r\n");
            foreach (var item in dic)
            {
                Console.WriteLine("key:" + item.Key + "_value:" + item.Value);
            }
            Console.WriteLine("\r\n----------ForEach结束-----------]\r\n");
        }

        /// <summary>
        /// 遍历键
        /// </summary>
        public void ForEachKey()
        {
            Console.WriteLine("\r\n[----------ForEachKey开始-----------\r\n");
            foreach (int item in dic.Keys)
            {
                Console.WriteLine("key:" + item + "_value:" + dic[item]);
            }
            Console.WriteLine("\r\n----------ForEachKey结束-----------]\r\n");
        }

        /// <summary>
        /// 遍历值
        /// </summary>
        public void ForEachValue()
        {
            Console.WriteLine("\r\n[----------ForEachValue开始-----------\r\n");
            foreach (string item in dic.Values)
            {
                Console.WriteLine("value:" + item);
            }
            Console.WriteLine("\r\n----------ForEachValue结束-----------]\r\n");
        }

        /// <summary>
        /// 通过这类方法可以对Dictionary排序后遍历
        /// </summary>
        public void ForArray()
        {
            Console.WriteLine("\r\n[----------ForArray开始-----------\r\n");
            List<int> list = new List<int>(dic.Keys);
            list.Sort();
            for (int i = 0; i < list.Count; i++)
            {
                Console.WriteLine("key:" + list[i] + "_value:" + dic[list[i]]);
            }
            Console.WriteLine("\r\n----------ForArray结束-----------]\r\n");
        }
    }

输出结果：