c# - Toggle flashlight in Windows Phone 8.1

Question

Can anyone say how to toggle flashlight in Windows Phone 8.1 using C#? It seems like there are lots of API changes in Windows Phone 8.1 and most of the API's in WP 8.0 are not supported. Answers are highly appreciated.

Answer 1

I'm able to use TorchControl on my Lumia 820 like this - first you have to specify which camera you will use - the default is front (I think that's why you may find some problems) and we want the back one - the one with flash light. Sample code:

// edit - I forgot to show GetCameraID:
private static async Task<DeviceInformation> GetCameraID(Windows.Devices.Enumeration.Panel desiredCamera)
{
    DeviceInformation deviceID = (await DeviceInformation.FindAllAsync(DeviceClass.VideoCapture))
        .FirstOrDefault(x => x.EnclosureLocation != null && x.EnclosureLocation.Panel == desiredCamera);

    if (deviceID != null) return deviceID;
    else throw new Exception(string.Format("Camera of type {0} doesn't exist.", desiredCamera));
}

// init camera
async private void InitCameraBtn_Click(object sender, RoutedEventArgs e)
{
    var cameraID = await GetCameraID(Windows.Devices.Enumeration.Panel.Back);
    captureManager = new MediaCapture();

    await captureManager.InitializeAsync(new MediaCaptureInitializationSettings
        {
            StreamingCaptureMode = StreamingCaptureMode.Video,
            PhotoCaptureSource = PhotoCaptureSource.VideoPreview,
            AudioDeviceId = string.Empty,
            VideoDeviceId = cameraID.Id
        });
}

// then to turn on/off camera
var torch = captureManager.VideoDeviceController.TorchControl;
if (torch.Supported) torch.Enabled = true;

// turn off
if (torch.Supported) torch.Enabled = false;

Note that it's a good idea to call captureManager.Dispose() after you finish with it.

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Note also that on some phones to turn on torch/flashlight you will need to start preview first.