System.IO.SerialPort throws System.PlatformNotSupportedException when calling from c++, but not from c#.

Question

I have a perplexing issue with the System.io.Ports package in a Class Library I built using c#/.NET6. I suspect it is a misconfiguration, but I'm not seeing much helpful documentation thus far on StackOverflow. As some background, I must support an old ANSI C Windows application that collects data from a usb device. To do so, we decided to create a c# component to do the job.

To test the component, I created three different test projects.

My first project simply created the component within a Console App. Everything worked as expected. Great! My second example was to build a separate c#/Winforms Application that referenced the component. Again, worked as expected. More good news!

The problem occurred when we built a similar c++ Console Application to access the Component. We referenced the DLL, an had no issues instantiating the component; however, when the component tries to instantiate the SerialPort class, the PlatformNotSupported Exception is thrown: "System.PlatformNotSupportedException System.IO.Ports is currently only supported on Windows "

I read in somewhere in a discussion group that this issue is that the default .netstandard dll is a cross platform DLL, and that the project should include the following addition.

<RuntimeIdentifier>win</RuntimeIdentifier>

No Luck with that mod for me, unfortunately.

Any ideas? The fundamental goal is to expose a few static methods to the ANSI C program. It seems that the DLLExport NuGet isn't getting much love, which was my first choice.

Answer 1

Hi,

Currently C++/CLI console app does not support .Net6, please consider using .Net Framework.(Common Language Runtime Support (/clr) and create your c# dll in .Net Framework. I created CLR Console APP(.Net Framework) template project and tested the snippet from document: SerialPort Class There is C++/CLI sample:

Best regards,

Minxin Yu

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Answer 2

I had a similar problem with the constructor of ServiceController, and managed to resolve the issue with specifying <RuntimeIdentifier>win-x86</RuntimeIdentifier> in the <PropertyGroup Label="Globals">