c# - 你调用的对象是空的。使用 TPM 设备客户端发送消息时

Question

我们有一个带有 bpm180 传感器的树莓派 pi3，我们像这样初始化连接

 TpmDevice myDevice = new TpmDevice(0); // Use logical device 0 on the TPM
                string hubUri = myDevice.GetHostName();
                string deviceId = myDevice.GetDeviceId();
                string sasToken = myDevice.GetSASToken();

                deviceClient = DeviceClient.Create(
                    hubUri,
                    Microsoft.Azure.Devices.Client.AuthenticationMethodFactory.
                        CreateAuthenticationWithToken(deviceId, sasToken), Microsoft.Azure.Devices.Client.TransportType.Amqp);

然后我们发送这样的消息:

public async void Bpm180Tick(object state)
        {
            string temperatureText;
            try
            {
                var sensorData = await _bmp180.GetSensorDataAsync(Bmp180AccuracyMode.UltraHighResolution);
                temperatureText = sensorData.Temperature.ToString("");
                temperatureText += "°C";
                var temperatureDataPoint = new
                {
                    deviceId = Global.GlobalTemperature,
                    valor = sensorData.Temperature,
                    fecha = DateTime.Now
                };
                //// actualizaciones de la interfaz de usuario... deben ser invocados en el subproceso de interfaz de usuario
                var messageString = JsonConvert.SerializeObject(temperatureDataPoint);
                var message = new Microsoft.Azure.Devices.Client.Message(Encoding.ASCII.GetBytes(messageString));
                //message.Properties["Ambiente"] = ambiente;
                //autoResetEvent.WaitOne();
                await deviceClient.SendEventAsync(message);
                //autoResetEvent.Set();
                var task = this.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
                {
                    Txt_Temperaura.Text = temperatureText;
                });
            }
            catch (Exception ex)
            {
                var a = ex.StackTrace;
                temperatureText = "Sensor Error: " + ex.Message;
            }


        }

但是我们正在获取对象引用，但错误似乎在库(sdk)中，而不是在我们的代码中

堆栈跟踪是这样的Ñ

  at Microsoft.Azure.Devices.Client.Transport.AmqpTransportHandler.<SendAmqpMessageAsync>d__27.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Devices.Client.Transport.AmqpTransportHandler.<SendEventAsync>d__19.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Devices.Client.Transport.ErrorDelegatingHandler.<>c__DisplayClass13_0.<<ExecuteWithErrorHandlingAsync>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Devices.Client.Transport.ErrorDelegatingHandler.<ExecuteWithErrorHandlingAsync>d__14`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Devices.Client.Transport.GateKeeperDelegatingHandler.<SendEventAsync>d__11.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.GetResult()
   at ActiveSense.Tempsense.Sensor.MainPage.<Bpm180Tick>d__23.MoveNext()

Answer 1

我想知道在异步代码运行时，TemperatureText 是否可能不再存在。我首先尝试将其设为静态类变量，看看会发生什么。