与WinRT组件进行操作

public delegate void TypedEventHandlerTSender,TResult>(TSender sender,TResult args)

EventHandlerT>

  public static void WinRTAsyncIntro()
        {
            //Provides access to common locations that contain user content. 
            //This includes content from a user‘s local libraries (such as Documents, Pictures, Music, and Videos),
            //HomeGroup, removable devices, and media server devices.
            IAsyncOperation asyncOp = KnownFolders.MusicLibrary.GetFileAsync("Song.mp3");//在音乐中查找一首歌.
            asyncOp.Completed = OpCompleted;
            Console.WriteLine("Operation...Completed!");
        }

        private static void OpCompleted(IAsyncOperation asyncInfo, AsyncStatus asyncStatus)
        {
            switch (asyncStatus)
            {
                case AsyncStatus.Completed:
                    Console.WriteLine("Completed!");
                    break;
                case AsyncStatus.Canceled:
                    Console.WriteLine("Canceled");
                    break;
                case AsyncStatus.Error:
                    Exception exception = asyncInfo.ErrorCode;//将异常转化成异常类.
                    Console.WriteLine("Error"+exception.HResult.ToString());
                    break;
                default:
                    break;

            }
        }

 [GuidAttribute(54, 0, 0, 192, 0, 0, 0, 0, 0, 0, 70)]
    [SupportedOn(100794368, Platform.Windows)]
    [SupportedOn(100794368, Platform.WindowsPhone)]
    [Version(100794368)]
    public interface IAsyncInfo
    {
        [SupportedOn(100794368, Platform.Windows)]
        [SupportedOn(100794368, Platform.WindowsPhone)]
        void Cancel();
        [SupportedOn(100794368, Platform.Windows)]
        [SupportedOn(100794368, Platform.WindowsPhone)]
        void Close();

        [SupportedOn(100794368, Platform.Windows)]
        [SupportedOn(100794368, Platform.WindowsPhone)]
        Exception ErrorCode { get; }
        [SupportedOn(100794368, Platform.Windows)]
        [SupportedOn(100794368, Platform.WindowsPhone)]
        uint Id { get; }
        [SupportedOn(100794368, Platform.Windows)]
        [SupportedOn(100794368, Platform.WindowsPhone)]
        AsyncStatus Status { get; }
    }

[SupportedOn(100794368, Platform.Windows)]
    [SupportedOn(100794368, Platform.WindowsPhone)]
    [Version(100794368)]
    public enum AsyncStatus
    {
        Started = 0,
        Completed = 1,
        Canceled = 2,
        Error = 3
    }

IAsyncAction----Task
IAsyncActionWithProgress---带有过程回调
IAsynOperation---带返回参数
IA十一年Operation With Progress---带过程回调,带返回参数的异步操作

 public static async void WinRTAsyncIntroEasy()
        {
            try
            {
                StorageFile storageFile = await KnownFolders.MusicLibrary.GetFileAsync("Song.mp3");

//正常结果
            }

//异常完成
            catch (OperationCanceledException) { Console.WriteLine("operation is canceled"); }
            catch(Exception e) { Console.WriteLine(e.HResult.ToString());  }

        }

 public static async Task TryConnectPlcAsync(CancellationToken token)
        {




            Plc plc = new Plc(CpuType.Logo0BA8, "192.167.0.0", 0, 1);

            Task t1 = plc.OpenAsync();//一个PLC异步函数,注意,异步函数的异常只能通过await来接收,它并不会直接导致出错.只是会终止线程.





            Task t2 = Task.Run(() =>//一种将没有取消功能的异步函数增加取消功能.
            {

                do
                {

                    log("token is"+token.IsCancellationRequested.ToString());
                    log(t1.Status.ToString());

                    if (token.IsCancellationRequested)
                    {
                        //token.ThrowIfCancellationRequested();
                        throw new Exception();
                    }
                    if (t1.IsFaulted) throw t1.Exception;

                } while (true);

            },token
            );
            try
            {

                await t2;
            }
            catch(Exception e)
            {
                log(e.Message+"in 1");
                //throw;        有的时候,将throw 抛给上层,并且运行完finally之后,就返回.//没的时候,不抛给上层.

            }

            finally
            {
                plc.Close();
                Console.WriteLine("plc is closed");
            }
           //正常完成的情况.

            Console.WriteLine("ok...");

        }
        public static async Task TryConnectPLCTest()
        {
            var tokenSource = new CancellationTokenSource();
            var token = tokenSource.Token;
            Task t = TryConnectPlcAsync( token);
            Thread.Sleep(100);
            //tokenSource.Cancel();用于 给 toekn设定一个取消标志.然后交给异步程序进行处理.(向异步程序传递取消标志).
            try
            {
                await t;//必须在这个地方捕捉错误,否则,异步任务的错误捕捉不到.
                Console.WriteLine(t.Status);
            }
            catch(Exception e)
            {
                log(e.GetType().ToString());
            }
            finally
            {
                tokenSource.Dispose();
            }
        }