static void Main(string[] args)
{
    //委托异步
    Action<string> showMessage = ShowMessage;
    IAsyncResult result = showMessage.BeginInvoke("测试异步委托",null, null);
    //那在异步线程未完成工作以前主线程将处于阻塞状态，等到异步线程结束，主线程才能继续工作
    showMessage.EndInvoke(result);
    Console.ReadLine();
              
}
static void ShowMessage(string x)
{
    string current = string.Format("当前线程id为{0}",Thread.CurrentThread.ManagedThreadId);
    Thread.Sleep(1000);
    Console.WriteLine(string.Format("{0},输入为{1}", current, x));
          
}
//csharp/6983