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我正在嘗試創建具有後臺任務的Windows通用應用程序。對象同步方法在使用Mutex時從非同步塊調用
我想寫一個後臺任務，觸發一個傳入的藍牙連接。 防止前景和背景創建連接。我正試圖在前景和背景中實現相同的互斥量。
當我從藍牙設備讀取數據時，出現以下錯誤。
對象同步方法從非同步塊
讓我驚訝的叫這個錯誤出現偶爾。我錯過了什麼？
這裏是我的代碼：
public sealed class RFBackgroundTask : IBackgroundTask
{
.... Variable declarations
public async void Run(IBackgroundTaskInstance taskInstance)
{
BackgroundTaskDeferral deferral = taskInstance.GetDeferral();
try
{
taskInstance.Canceled += new BackgroundTaskCanceledEventHandler(OnCanceled);
Debug.WriteLine("RFComm Task Running");
hotwatchConnection = taskInstance.TriggerDetails as RfcommConnectionTriggerDetails;
socket = hotwatchConnection.Socket;
reader = new DataReader(socket.InputStream);
// n = new Notification(hotwatchConnection.RemoteDevice.HostName);
await Read();
}
catch (System.Exception e)
{
Debug.WriteLine("RFComm Task Error: {0}", e.Message);
if (ismutexReleased == false)
{
Debug.WriteLine("Releaseing mutex because of error {0}:", e.Message);
connectionMutex.ReleaseMutex();
ismutexReleased = true;
}
}
finally
{
if (ismutexReleased == false)
{
Debug.WriteLine("Releasing Mutex 2");
connectionMutex.ReleaseMutex();
}
ismutexReleased = true;
}
deferral.Complete();
}
public IAsyncAction Read()
{
return Task.Run(async() =>
{
try
{
connectionMutex = new Mutex(false, CONNECTION_MUTEX_NAME);
// Attempt to wait for the mutex
var waitResult = connectionMutex.WaitOne();
if (waitResult)
{
Debug.WriteLine("Aquired Mutex Successfully");
}
// If the wait was not successful, fail the connect operation
if (!waitResult) { throw new TimeoutException(); }
if (reader != null)
{
uint length = 500;
reader.InputStreamOptions = InputStreamOptions.Partial;
uint len = await reader.LoadAsync(length);
String message = reader.ReadString(len);
Debug.WriteLine("Read " + message + " In the First Attemnpt");
var roamingSettings = Windows.Storage.ApplicationData.Current.RoamingSettings;
roamingSettings.Values["COMMAND"] = message;
//if(!message.StartsWith("01"))
//{
// await ProcessCommand(message);
//}
}
reader.Dispose();
socket.Dispose();
socket = null;
if (waitResult == true)
connectionMutex.ReleaseMutex();
ismutexReleased = true;
Debug.WriteLine("Released Mutex successfully after reading data");
}
catch (Exception e)
{
Debug.WriteLine(e.Message);
if (ismutexReleased == false)
{
Debug.WriteLine("Releaseing mutex because of error {0}:", e.Message);
connectionMutex.ReleaseMutex();
ismutexReleased = true;
}
throw;
}
finally
{
if (ismutexReleased == false)
{
connectionMutex.ReleaseMutex();
Debug.WriteLine("Releasing Mutex");
}
ismutexReleased = true;
}
}).AsAsyncAction();
}
}