Azure 物联网设备到云消息传递

Question

我想编写一个将设备消息写入云端的控制台应用程序。我已经使用 IOT 集线器编写了一个 cloud2-device 应用程序并预配置了我所有的集线器设备 ID 和工作。

这是我在 visual studio 中使用 C# connect-2-cloud-message 的示例代码。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Input;
using System.Diagnostics.Tracing;
using Microsoft.Azure.Devices.Client;

namespace Device2CloudApp
{
    class Program
    {

        // private our own fields for connection to IOT.

        private DeviceClient deviceClient;


        // use the device specific connection string.

        private const string IOT_HUB_CONN_STRING = "HostName=eNstaHub.azure-devices.net;DeviceId=GcobaniNumber1;SharedAccessKey="";
        private const string IOT_HUB_DEVICE = "GcobaniNumber1";
        private const string IOT_HUB_DEVICE_LOCATION = "West US";


        /*
         *  We calling all method inside the constructor for memory allocation. 
         */
       public  Program ()
        {

            SendMessageToIOTHubAsync(deviceClient).Wait();

        }

        private async Task SendMessageToIOTHubAsync(DeviceClient deviceClient)
        {
            try
            {
                var payload = "{" +
                "\"deviceId\":\"" + IOT_HUB_DEVICE + "\", " +
                "\"location\":\"" + IOT_HUB_DEVICE_LOCATION + "\", " +
                "\"localTimestamp\":\"" + DateTime.Now.ToLocalTime() + "\"" +
                "}";

                var msg = new Message(Encoding.UTF8.GetBytes(payload));
                System.Diagnostics.Debug.WriteLine("\t{0} > Sending message:[{1}]", DateTime.Now.ToLocalTime(), payload);
                await deviceClient.SendEventAsync(msg);
            }catch(Exception ex)
            {
                System.Diagnostics.Debug.WriteLine("!!!" + ex.Message);
            }
        }


        static void Main(string[] args)
        {
            DeviceClient deviceClient = DeviceClient.CreateFromConnectionString(IOT_HUB_CONN_STRING);

            // creating a Constructor here for method declarion.

            Program prg = new Program();
        }
    }
}

在我的控制台上，它没有连接到云物联网集线器；它抛出一个 System.NullreferenceException.

Answer 1

您在 main 方法中有一个本地 deviceClient 方法，这不是与 Azure 通信时使用的方法。

删除那个，然后创建您在 class 中拥有的实例。

Answer 2

它应该像下面的代码一样工作。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Input;
using System.Diagnostics.Tracing;
using Microsoft.Azure.Devices.Client;

namespace Device2CloudApp
{
    class Program
    {
        // private our own fields for connection to IOT.
        private DeviceClient deviceClient;    

        // use the device specific connection string.

        private const string IOT_HUB_CONN_STRING = "HostName=eNstaHub.azure-devices.net;DeviceId=GcobaniNumber1;SharedAccessKey="";
        private const string IOT_HUB_DEVICE = "GcobaniNumber1";
        private const string IOT_HUB_DEVICE_LOCATION = "West US";


        /*
         *  We calling all method inside the constructor for memory allocation. 
         */
        public  Program ()
        {

            DeviceClient deviceClient = DeviceClient.CreateFromConnectionString(IOT_HUB_CONN_STRING);
            SendMessageToIOTHubAsync(deviceClient).Wait();

        }

        private async Task SendMessageToIOTHubAsync(DeviceClient deviceClient)
        {
            try
            {
                var payload = "{" +
                "\"deviceId\":\"" + IOT_HUB_DEVICE + "\", " +
                "\"location\":\"" + IOT_HUB_DEVICE_LOCATION + "\", " +
                "\"localTimestamp\":\"" + DateTime.Now.ToLocalTime() + "\"" +
                "}";

                var msg = new Message(Encoding.UTF8.GetBytes(payload));
                System.Diagnostics.Debug.WriteLine("\t{0} > Sending message:[{1}]", DateTime.Now.ToLocalTime(), payload);
                await deviceClient.SendEventAsync(msg);
            }catch(Exception ex)
            {
                System.Diagnostics.Debug.WriteLine("!!!" + ex.Message);
            }
        }


        static void Main(string[] args)
        {
            // creating a Constructor here for method declarion.

            Program prg = new Program(deviceClient);
        }
    }
}

Answer 3

请试试这个。希望对您有所帮助。

先声明常量。

    private const string DeviceKey = "your secret key";
    private const string DeviceId = "DeviceName";

然后根据SymmetricKey创建连接字符串

     _deviceClient = DeviceClient.Create(IotHubUri, new 
     DeviceAuthenticationWithRegistrySymmetricKey(DeviceId, DeviceKey), TransportType.Mqtt);

模拟器示例代码：

   using System;
   using System.Text;
   using System.Threading.Tasks;
   using Microsoft.Azure.Devices.Client;
   using Newtonsoft.Json;
   namespace SimulatedDevice
   {
   class Program
    {
    private const string IotHubUri = "YourHubName.azure-devices.net";
    private const string DeviceKey = "Secret Key";
    private const string DeviceId = "DeviceId";
    private const double MinVoltage = 40;
    private const double MinTemperature = 10;
    private const double MinHumidity = 50;
    private static readonly Random Rand = new Random();
    private static DeviceClient _deviceClient;
    private static int _messageId = 1;

    static void Main(string[] args)
    {
        Console.WriteLine("Simulated device\n");
        _deviceClient = DeviceClient.Create(IotHubUri, new DeviceAuthenticationWithRegistrySymmetricKey(DeviceId, DeviceKey), TransportType.Mqtt);
        _deviceClient.ProductInfo = "Simulated_Client";

        SendDeviceToCloudMessagesAsync();
        Console.ReadLine();
    }

    private static async void SendDeviceToCloudMessagesAsync()
    {
        while (true)
        {
            var currentVoltage = MinVoltage + Rand.NextDouble() * 15;
            var currentTemperature = MinTemperature + Rand.NextDouble() * 20;
            var currentHumidity = MinHumidity + Rand.NextDouble() * 25;

            var telemetryDataPoint = new
            {

                deviceId = DeviceId,
                timestamp = DateTime.UtcNow,
                Temperature = currentTemperature,
                Humidity = currentHumidity,
                Voltage = currentVoltage,

            };
            var messageString = JsonConvert.SerializeObject(telemetryDataPoint);
            var message = new Message(Encoding.ASCII.GetBytes(messageString));

            await _deviceClient.SendEventAsync(message);
            Console.WriteLine("{0} > Sending message: {1}", DateTime.Now, 
             messageString);

            await Task.Delay(2000);
          }
         }

      }
     }

Azure 物联网设备到云消息传递

azure iot device to cloud messaging

c#

azure

iot