ReadingChanged never called for Accelerometer on WP8 - windows-phone-8

Question

I'm trying to use the C++ Accelerometer interface in the Windows::Devices::Sensors namespace on the Windows Phone 8. The code is very similar to a C# project I have that works, but I can't get the C++ event to fire like I can with my C# code.
My C++ code is a C# project with a C++ component, the C++ component just opens up the Accelerometer device for reading, and then tries to setup an event to fire whenever data is ready:
AccelerometerWrapper::AccelerometerWrapper() {
Accelerometer^ acc = Accelerometer::GetDefault();
accReading = acc->ReadingChanged::add( ref new TypedEventHandler<Accelerometer^, AccelerometerReadingChangedEventArgs^>(this, &AccelerometerWrapper::ReadingChanged));
}
void AccelerometerWrapper::ReadingChanged(Accelerometer^ sender, AccelerometerReadingChangedEventArgs^ e) {
...
}
Unfortunately, my ReadingChanged() function is never being called. I've looked around for a Start() method or somesuch but I can't find anything. I'm basing most of my knowledge off of the AccelerometerCPP example, but I can't actually test that as it is a generic WinRT (e.g. Windows 8, not Windows Phone 8) example, and my computer does not have an accelerometer. Everything compiles and runs, the event is just never triggered.
EDIT: I have successfully run a test to verify that I can manually call acc->GetCurrentReading(), so the accelerometer is working, it just seems to be the event that is not getting triggered.
Thank you in advance!

Answer 1

I'm not a C++ expert, but the new Accelerometer sensor works on my machine using C#.
private void MainPage_Loaded(object sender, RoutedEventArgs e)
{
var accelerometer = Accelerometer.GetDefault();
if (accelerometer != null)
{
accelerometer.ReadingChanged += accelerometer_ReadingChanged;
}
}
void accelerometer_ReadingChanged(Accelerometer sender, AccelerometerReadingChangedEventArgs args)
{
Debug.WriteLine(args.Reading.AccelerationX + ", " + args.Reading.AccelerationY + "," + args.Reading.AccelerationZ);
}
When we run that code snippet we can see the following expected output:
Just a guess for C++, do you need to cache the Accelerometer instance somewhere instead of letting it go out of scope?