在摄像头完全初始化之前锁定手机的问题.当我解锁手机时，它坏了

我正在开发一个相机应用程序，当我在相机完全初始化之前离开该应用程序并试图返回到它们时，我遇到了问题。在我的OnNavigatedFrom方法中，我有：

protected override void OnNavigatedFrom(NavigationEventArgs e)
        {
    try
            {
                if (cameraInit)
                {
                    Dispatcher.BeginInvoke(() => { 
                        if (cam != null)
                        {
                            cam.Dispose();
                            cam.CaptureCompleted -= cam_CaptureCompleted;
                            cam.CaptureImageAvailable -= cam_CaptureImageAvailable;
                            cam.AutoFocusCompleted -= cam_AutoFocusCompleted;
                            CameraButtons.ShutterKeyPressed -= OnButtonFullPress;
                            cam = null;
                            cameraInit = false;
                        }
                    });
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
}

这是OnNavigatedTo我的方法：

protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
        {
// Check to see if the camera is available on the device.
        if (PhotoCamera.IsCameraTypeSupported(CameraType.Primary) == true)
        {
            if (cam == null)
            {
                cam = new Microsoft.Devices.PhotoCamera(CameraType.Primary);
                //Create the camera event handlers
                //// Event is fired when the capture sequence is complete.
                cam.CaptureCompleted += new EventHandler<CameraOperationCompletedEventArgs>(cam_CaptureCompleted);
                //// Event is fired when the capture sequence is complete and an image is available.
                cam.CaptureImageAvailable += new EventHandler<Microsoft.Devices.ContentReadyEventArgs>(cam_CaptureImageAvailable);
                //// The event is fired when auto-focus is complete.
                cam.AutoFocusCompleted += new EventHandler<CameraOperationCompletedEventArgs>(cam_AutoFocusCompleted);
                //// The event is fired when the shutter button receives a full press.
                cam.Initialized += cam_Initialized;
                CameraButtons.ShutterKeyPressed += OnButtonFullPress;
            }
            ////Set the VideoBrush source to the camera.
            canvasCamBrush.SetSource(cam);
}

这是我的cam_initialized方法：

void cam_Initialized(object sender, CameraOperationCompletedEventArgs e)
    {
        if (e.Succeeded)
        {
            cameraInit = true;
            if (cameraInit)
            {
                cam.FlashMode = FlashMode.Off;
            }
        }
    }

主要问题是，当onNavigatedFrom方法启动时，凸轮未完全初始化，然后当我返回应用程序时，它会中断OnNavigatedTo的方法，因此我需要在那里等待，直到cam_initialized方法被激发，然后再运行onNavigatedProm。

以下是另一个有这个问题但我无法解决的人的例子：

初始化时出现PhotoCamera问题

谢谢大家，L

protected override void OnNavigatedFrom(NavigationEventArgs e)
        {
         try
            {
             while (!cameraInit)
                {
                    System.Threading.Thread.Sleep(100);
                }
                if (cameraInit)
                {
                    Dispatcher.BeginInvoke(() => { 
                        if (cam != null)
                        {
                            cam.Dispose();
                            cam.CaptureCompleted -= cam_CaptureCompleted;
                            cam.CaptureImageAvailable -= cam_CaptureImageAvailable;
                            cam.AutoFocusCompleted -= cam_AutoFocusCompleted;
                            CameraButtons.ShutterKeyPressed -= OnButtonFullPress;
                            cam = null;
                            cameraInit = false;
                        }
                    });
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
}