未设置为对象实例的对象引用.在使用TPM设备客户端发送消息时

我们有一个带有bpm180传感器的树莓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;
            }

        }

然而，我们正在获取和对象引用，但错误似乎是在库(sdk)，而不是在我们的代码

堆栈跟踪是thisÑ

  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()

我想知道是否有可能，温度文本不再存在的时间异步代码正在运行。我将首先尝试使其成为静态类变量，看看会发生什么。

很可能SAS令牌过期，但AMQP库没有给您有用的错误。要确认这一点，请使用带有SharedAccessKey的连接字符串:

DeviceClient.CreateFromConnectionString("...;SharedAccessKey=xyz;...", TransportType.Amqp);

如果有效，您需要考虑更新您的SAS令牌(不要在产品代码中留下SharedAccessKey !)。如果出现相同的错误，则问题出在代码的其他地方。

SAS令牌可能过期。

另一方面，由于azure - iot - sdk是开源的，您可以直接引用sdk源代码来检查错误。

删除你的项目nuget引用"Microsoft.Azure.Devices.Client"
将azure-iot-sdk存储库与您的项目并行克隆
在项目中引用Microsoft.Azure.Devices.Client.WinRT

您应该能够调试AmqpTransportHandler。SendAmqpMessageAsync的源代码，看看问题到底是什么。

我自己没有运气在Windows IoT Core 14393的RPi3上重现您的问题。

发生这种情况是因为TPM库中有一个错误，我提交了一个问题并修复了拉取请求。

这是问题的链接:https://github.com/ms-iot/security/issues/11

SAS令牌立即过期。它能工作一段时间的唯一原因是物联网集线器允许一些时钟偏差。我还在等待NuGet上的Microsoft.Devices.Tpm的新版本

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