基於委託的異步回調

 異步回調時在調用 BeginInvoke時提供的回調方法，主線程就沒必要再等待異步線程工做完畢，異步線程在工做結束後會主動調用提供的回調方法。

    class Program

    {

        public delegate void PrintDelegate(string content);

        static void Main(string[] args)

        {

            int threadId = Thread.CurrentThread.ManagedThreadId;

            PrintDelegate printDelegate = new PrintDelegate(Print);

 

            Console.WriteLine("[主線程id:{0}]\t開始調用打印的方法...", threadId);

            IAsyncResult result = printDelegate.BeginInvoke("Hello Word!", PrintComplete,printDelegate);

            Thread.Sleep(1000);

            Console.ReadLine();

 

        }

 

        public static void Print(string content)

        {

            int threadId = Thread.CurrentThread.ManagedThreadId;

            Console.WriteLine("[當前線程id:{0}]\t{1}",threadId,content);

            Thread.Sleep(1000);

        }

 

        private static void PrintComplete(IAsyncResult asyResult)

        {

            if (null == asyResult)

            {

                throw new ArgumentException();

            }

            int threadId = Thread.CurrentThread.ManagedThreadId;

 

            (asyResult.AsyncState as PrintDelegate).EndInvoke(asyResult);

            Console.WriteLine("[當前線程id:{0}]\t打印方法調用完畢。", threadId);

        }

    }