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c#uwpc++-cli

Is it possible to add PnpObjectType_DeviceInterface to UWP Package.appxmanifest <DeviceCapability>?

My Win32 application normally communicates with a serial device via a USB interface. For diagnostic and development purposes for many years I have made use of the Com0Com utility which creates serial loopback interfaces. I am now writing a UWP(Non-Store) version of my application.

The Com0Com ports are visible when calling

// Construct AQS String for all serial devices on system
Platform::String ^serialDevices_aqs = Windows::Devices::SerialCommunication::SerialDevice::GetDeviceSelector();

// Identify all paired devices satisfying query
return Windows::Devices::Enumeration::DeviceInformation::FindAllAsync(serialDevices_aqs);

Add looking at the device_ID value of the the com0com ports fetched from my fetch of the list of serial devices

[Id] = L"\\\\?\\com0com#port#CNCA1#{86e0d1e0-8089-11d0-9ce4-08003e301f73}"
[Type] = PnpObjectType_DeviceInterface (1)
[1] = {L"System.Devices.DeviceInstanceId" = L"com0com\\port\\CNCA1"}

And if I modify the Package.appxmanifest file per

https://learn.microsoft.com/en-us/uwp/schemas/appxpackage/appxmanifestschema/element-devicecapability

<Capabilities>
    <DeviceCapability Name="serialcommunication">
        <Device Id="any">
            <Function Type="name:serialPort" />
        </Device>
        <!-- added below -->
        <DeviceCapability Name="86e0d1e0-8089-11d0-9ce4-08003e301f73"/>
    </DeviceCapability>
</Capabilities>

alas

return Concurrency::create_task(SerialDevice::FromIdAsync(device->Id), childToken)
        .then([this](SerialDevice ^serial_device)

alway passes null to the lambda function null for any of the selected com0com ports.

Am I doing this incorrectly or is it not possible within the UWP constraints.

Solution

  • Am I doing this incorrectly or is it not possible within the UWP constraints.

    Unfortunately, it seems like your situation is not supported by FromIdAsync() method. According to this document:

    System-internal or on-chassis serial ports may be enumerated by DeviceInformation.FindAllAsync(), but cannot be opened by SerialDevice.FromIdAsync() because they currently are not supported. However, serial ports connected over USB, such as on USB-to-Serial cables are supported.

    com0com you mentioned here seems to be the virtual serial port driver which is not connected over USB and may not be supported.