UsbDevice.GetDeviceClassSelector(UsbDeviceClass) Method

Definition

Namespace:

Windows.Devices.Usb

Gets an Advanced Query Syntax (AQS) string that the app can pass to DeviceInformation.FindAllAsync in order to find a specific type of USB device.

public:
 static Platform::String ^ GetDeviceClassSelector(UsbDeviceClass ^ usbClass);

 static winrt::hstring GetDeviceClassSelector(UsbDeviceClass const& usbClass);

public static string GetDeviceClassSelector(UsbDeviceClass usbClass);

function getDeviceClassSelector(usbClass)

Public Shared Function GetDeviceClassSelector (usbClass As UsbDeviceClass) As String

Parameters

usbClass

UsbDeviceClass

A UsbDeviceClass object for the device class specified by the app.

Returns

String

Platform::String

winrt::hstring

String formatted as an AQS query.

Examples

protected override async void OnLaunched(LaunchActivatedEventArgs args)
{
    byte deviceClass = 0xf0;
    byte deviceSubclass = 0x01;

    var myDevices = await Windows.Devices.Enumeration.DeviceInformation.FindAllAsync(
                          UsbDevice.GetDeviceClassSelector(
                          new UsbDeviceClass() {
                          Class = deviceClass, Subclass = deviceSubclass }));

    UsbDevice device = null;

    foreach (var device in myDevices)
    {
        if (IsMyDevice(device))
        {
            device = await UsbDevice.FromIdAsync(device.Id);
        }
    }

    if (device == null)
    {
        ShowError("Usb device not found");
        return;
    }

}

Remarks

You can search for a UsbDevice in the enumerated collection of devices by specifying class code, sub class code, or protocol code. To do this,

1. Create a UsbDeviceClass object by specifying ClassCode, SubclassCode, and ProtocolCode property values. Alternatively, you can call the constructor by specifying a particular UsbDeviceClasses property.
2. Call GetDeviceClassSelector and pass that new class. The call retrieves an AQS string.
3. Call FindAllAsync and pass the string to get the UsbDevice object.