Question

我正在实现Azure功能，以便在Iot Hub事件触发器上向设备发送消息。问题是使用未定义的名称空间时出现很多编译错误。

该示例基于本文：https://sandervandevelde.wordpress.com/2016/06/14/closing-the-windows-iot-core-feedback-loop-using-azure-functions/

using System;
using Microsoft.Azure.Devices;
using System.Text;
using Newtonsoft.Json;

public static void Run(string myIoTHubMessage, ILogger log)
{
    var connectionString = "HostName=iot-hub-teste.azure-devices.net;SharedAccessKeyName=service;SharedAccessKey=hiden";

    var serviceClient = ServiceClient.CreateFromConnectionString(connectionString);

    var message = JsonConvert.DeserializeObject<Command>(myEventHubMessage);

    var commandMessage = new Message(Encoding.ASCII.GetBytes("Cloud to device message."));

    serviceClient.SendAsync("MyNodeDevice", commandMessage);
}

project.json

{
  "frameworks": {
  "net46":{
    "dependencies": {
      "Microsoft.Azure.Devices": "1.4.1"
      }
    }
  }
}

错误：

2019-08-23T18:03:47.255 [Error] Function compilation error
Microsoft.CodeAnalysis.Scripting.CompilationErrorException : Script compilation failed.
   at async Microsoft.Azure.WebJobs.Script.Description.DotNetFunctionInvoker.CreateFunctionTarget(CancellationToken cancellationToken) at C:\azure-webjobs-sdk-script\src\WebJobs.Script\Description\DotNet\DotNetFunctionInvoker.cs : 314
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at async Microsoft.Azure.WebJobs.Script.Description.FunctionLoader`1.GetFunctionTargetAsync[T](Int32 attemptCount) at C:\azure-webjobs-sdk-script\src\WebJobs.Script\Description\FunctionLoader.cs : 55
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at async Microsoft.Azure.WebJobs.Script.Description.DotNetFunctionInvoker.GetFunctionTargetAsync(Boolean isInvocation) at C:\azure-webjobs-sdk-script\src\WebJobs.Script\Description\DotNet\DotNetFunctionInvoker.cs : 183
2019-08-23T18:03:47.427 [Error] run.csx(3,23): error CS0234: The type or namespace name 'Devices' does not exist in the namespace 'Microsoft.Azure' (are you missing an assembly reference?)
2019-08-23T18:03:47.477 [Error] run.csx(13,25): error CS0103: The name 'ServiceClient' does not exist in the current context
2019-08-23T18:03:47.541 [Error] run.csx(15,49): error CS0246: The type or namespace name 'Command' could not be found (are you missing a using directive or an assembly reference?)
2019-08-23T18:03:47.630 [Error] run.csx(15,58): error CS0103: The name 'myEventHubMessage' does not exist in the current context
2019-08-23T18:03:47.694 [Error] run.csx(17,30): error CS0246: The type or namespace name 'Message' could not be found (are you missing a using directive or an assembly reference?)
2019-08-23T18:03:47.766 [Error] Executed 'Functions.msg_to_device' (Failed, Id=de327298-1973-4bc5-82b6-0c7b05835dae)
Script compilation failed.

Answer 1

1）请在project.json中添加对Microsoft.Azure.Devices（1.18.1）和Microsoft.Azure.Devices.Client（1.21.0）的引用，然后将其包含在功能代码中

           using Microsoft.Azure.Devices;
           using Microsoft.Azure.Devices.Client;

2）博客文章中缺少命令类：

            public class Command
            {
              public string devicename {get; set;}
              public int action {get; set;}
            }

3）没有有关myEventHubMessage的引用。您正在使用myIoTHubMessage代替它。

4）使用Microsoft.Azure.Devices.Client应该可以获取Message类。

这就是我在普通C＃类中所做的。也许您可以根据需要在Azure Functions中调整此代码。

         CloudToDeviceMethod cloudtoDeviceMethod = new          
         CloudToDeviceMethod(DeviceMethod, 
         TimeSpan.FromSeconds(30), TimeSpan.FromSeconds(30)); 

         ServiceClient serviceClient = null;

         serviceClient = 
         ServiceClient.CreateFromConnectionString("HostName=myhub.azure- 
         devices.net;SharedAccessKeyName=service;SharedAccessKey=xxxxxxxxxxxxxxxx");

         await serviceClient.OpenAsync();  

         var response=await serviceClient.InvokeDeviceMethodAsync(DeviceId, 
         cloudtoDeviceMethod);   

         var json = @"{""Response:" + 
         response.GetPayloadAsJson()+@""",Status:""" + 
         response.Status + @"}";    

         if (serviceClient != null)
         {
            await serviceClient.CloseAsync();
         }

Answer 2

测试表明Microsoft.Azure.Devices对Newtonsoft.Json有依赖性。好的部分是在博客中添加了依赖关系。您可以尝试在project.json中的Newtonsoft.Json（9.0.1）中添加依赖关系并尝试。一定看起来这些软件包Microsoft.Azure.Devices和Microsoft.Azure.Devices.Client尚未安装，这就是为什么代码抱怨名称空间不存在的原因。

另一种替代方法是先在Visual Studio中编写函数，然后将其部署到Azure。这样一来，您就可以在将计算机上的所有依赖项放入云之前进行大量测试。希望这会有所帮助。

无法在Azure Iot Hub中将云编译为设备功能

2 个答案: