C# 轮循回调

class Program
    {
        static void Main(string[] args)
        {
            Func<int> func = new Func<int>(GetInt);

            var iar = func.BeginInvoke(new AsyncCallback(Show), null);
            while (!iar.IsCompleted)
            {
                Thread.Sleep(1000);
                Console.WriteLine("收到了您的提示！");
            }
            Console.WriteLine("处理结果为{0}！",func.EndInvoke(iar));
            Console.ReadKey();
        }

        private static void Show(IAsyncResult iar)
        {
            while (iar.IsCompleted)
            {
                Console.WriteLine("执行完毕！");
                break;
            }
        }

        private static int GetInt()
        {
            for (var i = 0; i < 10; i++)
            {
                Console.WriteLine("请稍等，我正在执行，需要点时间");
                Thread.Sleep(1000);
            }
            return 1;
        }

    }