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  1. #1
    Registered User
    Join Date
    Jul 2013

    FlashLight in WindowsPhone 7


    I am working on windows phone 7 Flash light application. I have used the torch light sample application class to implement the required functionality in my application. For that I am using Videocamera class. Please see the following piece of code

    Assembly mediaExtendedAssembly = Assembly.Load("Microsoft.Phone.Media.Extended, Version=, Culture=neutral, PublicKeyToken=24eec0d8c86cda1e");
    Type videoCameraType = mediaExtendedAssembly.GetType("Microsoft.Phone.VideoCamera");
    ConstructorInfo videoCameraConstructor = videoCameraType.GetConstructor(new Type[] { cameraSourceType });
    _videoCamera = videoCameraConstructor.Invoke(new object[] { cameraSource });

    // Set the properties and methods.
    _videoCameraLampEnabledPropertyInfo = videoCameraType.GetProperty("LampEnabled");
    _videoCameraStartRecordingMethod = videoCameraType.GetMethod("StartRecording");

    public void StartRecording()

    // Invoke the start recording method on the video camera object.
    _videoCameraStartRecordingMethod.Invoke(_videoCamera, new object[0]);

    Using the above code it was able to set the flash light on. Inorder to stop the flash light, I have added following lines to the above code.

    _videoCameraStopRecordingMethod = videoCameraType.GetMethod("StopRecording");
    public void StopRecording()
    _videoCameraStopRecordingMethod.Invoke(_videoCamera, null);
    ie: By passing null as a parameter it was able to stop the flash light. Like this way I am turning ON and OFF the FlashLight for 2 to 3 times. But If I navigate from the current page to next page and comes back to the flash application page ,it is crashing at the time of Initialisation.

    ie: while calling the line,

    _cameraVisualizerSetSourceMethod.Invoke(_cameraVisualizer, new object[] { camera.InnerCameraObject });

    I couldn't dispose the video camera objects. Couldn't free its resources. Even if I set null to videocamera object ,its not getting deinitialised. Could you please tell me how to free its resources.
    Any kind of help would be greatly appreciated.


  2. #2
    Nokia Developer Champion
    Join Date
    Mar 2013

    Re: FlashLight in WindowsPhone 7

    Without looking at the API in detail I'd say that there is a "Dispose()"-method on the _videoCamera object. So calling _videoCamera.Dispose() should make it release it's resources.

    Is there a specific reason why you are loading the Assembly using Reflection and are doing all the invocations using Reflection instead of simply using a reference to the Assembly in your code and invoked the methods normally?

  3. #3
    Registered User
    Join Date
    Jul 2013

    Re: FlashLight in WindowsPhone 7

    Hi Dev,,

    Can't use Dispose() function as there is no built in function for _videocamera object.
    I am declaring the videocamera object as follows.

    Private object _videoCamera;

    and _videoCamera doesn't have any built in functions for disposing.

    So I tried the following code:

    _videoCamera = null;


    These lines make the app somewhat stable. But it would be nice if u could suggest a better method for this.


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