NotImplementedException while calling Microsoft.Azure.Devices.ServiceClient.CreateFromConnectionString

EE NTU 96

First, I am trying to make a Hololens app that can interact with IoT devices by Unity, and I just add Microsoft.Azure.Devices.dll into my Assets/Plugins folder and then add other .dll files until there is no compile error.
Now, when I call

s_serviceClient = ServiceClient.CreateFromConnectionString(HubConnectionString, TransportType.Amqp);

I got a NotImplementedException, and the error message is like

What's going wrong?

Thanks.

AshokPeddakotla-MSFT 27,966 Reputation points

2022-09-08T05:03:52.533+00:00

@EE NTU Wanted to follow up with you to understand whether the below information helped. Please let us know if there are any other queries.
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2 answers

Sander van de Velde 29,271 Reputation points MVP

2022-08-06T10:08:38.66+00:00
Hello @EE NTU ,

it seems you want to connect your hololens as a device to the IoT Hub.

as seen here, you need to create a DeviceClient:

var connectionString = "[the connection string of your device]"; using var deviceClient = DeviceClient.CreateFromConnectionString(connectionString);

The service client is for controlling the IoT Hub service itself (together with other classes) and it needs the connection string of the IoT hub itself. It's not recommended to expose the IoT Hub connection string outside Azure / inside a device.
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EE NTU 96 Reputation points

2022-08-06T14:08:28.813+00:00

Thanks, but actually, what I want to do is to call the direct method of connected devices, and I am trying to do what this document doing in Unity. Or there is other way to control a device?

Sander van de Velde 29,271 Reputation points MVP

2022-08-06T15:15:51.76+00:00

Hello @EE NTU ,

once you have connected your (hololens) device to the IoT Hub, there are three ways to control your device:

Device twin desired properties. Great for sending configurations ASYNC.

Direct Methods. Great when you have a LIVE connection to a device and you want to receive an answer to your 'question/command'. Note: methods names are case-sensitive

Cloud messages. Send a ASYNC message to a device. It will be picked up when the client wants to.

All three solutions solution need client-side code to be executed.

Check out this blog post for all code samples.

This is free training on MS Learn about Azure IoT, check out this module regarding device twin and direct methods.

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EE NTU 96 Reputation points

2022-08-06T16:29:24.607+00:00

Thank you, I will check them out, those should be helpful. and sorry for the misleading, but Hololens is not the device I want to control. I mean I want to control other devices by my Hololens app so I still want to know why this exception raised. By the way, I also tried creating a DeviceClient and I got same exception.

Sander van de Velde 29,271 Reputation points MVP

2022-08-06T17:12:31.413+00:00

Hello @EE NTU ,

thanks for the extra information, this makes it more clear.

I'm not sure why the connection cannot be made. The call is pretty straightforward.

Still, I recommend a slightly more elaborate architecture.

Expose an Azure function that takes care of sending Direct Method calls to the IoT Hub. This way, your IoT Hub connection string is not living on that single hololens and multiple hololenses can connect (in their own secure way) to the azure function.
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Bruce (SqlWork.com) 56,931 Reputation points

2022-08-06T17:40:30.39+00:00

One of the design decisions with .netstandard, was while all api methods are defined, they do not need to implemented on all platforms, they are free to throw the not implemented error.

The error indicates that .net platform hosting your code did not implement an api required by this library. Probably websocket support.
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EE NTU 96 Reputation points

2022-08-07T14:51:27.42+00:00

Got it. Thank you!
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