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Editorial Team
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Asked: 2026-06-15T04:41:27+00:00

I’m trying to write my own controller for a USB device instead of using

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I’m trying to write my own controller for a USB device instead of using the SDK that comes with the product (I feel the sdk is sub-par).

The USB Device is plugged into the SAME SERVER that this application is running on.

So I decided to head over to Nuget and grab the HidLibrary

PM> Install-Package hidlibrary

and I proceeded to follow the example found on GitHub.

First I went into my control panel to verify the VendorID and the ProductID

VendorID and ProductID

And I dropped it into my code.

Then I set a breakpoint on the line that grabs the device, but unfortunately it always comes back null.

using HidLibrary;
public class MyController : ApiController
{

    private const int VendorId = 0x0BC7;
    private const int ProductId = 0x0001;

    private static HidDevice _device;

    // POST api/<controller>
    public string Post(CommandModel command)
    {

        _device = HidDevices.Enumerate(VendorId, ProductId).FirstOrDefault();

        if (_device != null)
        {
            // getting here means the device exists
        }
        else
        {
            // ending up here means the device doesn't exist
            throw new Exception("device not connected");
        }
        return null;
    }

I’m hoping it’s something silly, and not some deal-breaking permissions issue regarding connecting to a USB device directly from an IIS worker.

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1 Answer

  1. Editorial Team

    Despite your hopes to be something silly, it is not. You have some deal-breaking permission issues. If you will browse Mike O’Brien’s code from GitHub of the Hid Library you will see that it calls Win32 API functions located in: kernel32.dll, setupapi.dll, user32.dll, hid.dll (Native.cs).

    The enumeration itself it’s done through setupapi.dll functions. It browse all the installed devices and filters what it’s need it.

    So… I think it’s a security issue to execute kernel32.dll code directly from a web-app in IIS with anonymous authentication, don’t you?

    If you really need to communicate with that HID (who knows maybe it’s a temperature sensor, or something else) I would do a separate Windows service and the IIS hosted web app would communication through WCF with this service. This service would like a proxy.

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