从本机C#代码（Windows 10）打开摄像头用户界面

我需要从cordova javascript调用WinRT中的本机函数。此函数应以本机方式（使用C#）打开CameraUI

限制是无法使用摄像头插件打开摄像头。它必须从本机代码打开

下面的代码是WinRT组件。当从Cordova Javascript调用它（Test.TestController.openCamera（）；）时，它不会打开摄像头。但是，如果我从本机windows应用程序调用它，它将能够打开摄像头。是否有解决方案来解决此问题

总之，调用本机WinRT组件以打开自定义相机UI所需的Windows混合应用程序（JavaScript）

名称空间测试 { 公共密封类测试控制器 { 公共静态异步void openCamera（） { System.Diagnostics.Debug.WriteLine（“调用openCamera”）； 预览预览=新建预览（）； preview.openCam（）； }

}

public sealed class Preview
{
    MediaCapture mediaCapture;
    public async void openCam()
    {
        await StartPreviewAsync();
    }
    private async Task StartPreviewAsync()
    {
        try
        {

            CaptureElement preview = new CaptureElement();
            StackPanel stackPanel = new StackPanel { Orientation = Orientation.Vertical };
            preview.Stretch = Windows.UI.Xaml.Media.Stretch.UniformToFill;
            preview.Width = 400;
            preview.Height = 650;
            stackPanel.Width = 400;
            stackPanel.Height = 650;
            stackPanel.Children.Add(preview);

            //TODO : Instead of using Windows.Current , need to find a way to get reference of the main application view.
            //Window.Current.Content = stackPanel;

            CoreApplicationView newView = CoreApplication.CreateNewView();
            int newViewId = 0;
            await newView.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
            {

                Window.Current.Content = stackPanel;
                // You have to activate the window in order to show it later.
                Window.Current.Activate();

                newViewId = ApplicationView.GetForCurrentView().Id;
            });
            bool viewShown = await ApplicationViewSwitcher.TryShowAsStandaloneAsync(newViewId);


            var _deviceInformation = await GetCameraDeviceInfoAsync(Windows.Devices.Enumeration.Panel.Back);

            var settings = new MediaCaptureInitializationSettings();
            settings.StreamingCaptureMode = StreamingCaptureMode.Video;
            settings.PhotoCaptureSource = PhotoCaptureSource.VideoPreview;
            settings.AudioDeviceId = "";
            if (_deviceInformation != null)
                settings.VideoDeviceId = _deviceInformation.Id;

            mediaCapture = new MediaCapture();
            await mediaCapture.InitializeAsync(settings);
            mediaCapture.SetPreviewRotation(VideoRotation.Clockwise90Degrees);
            preview.Source = mediaCapture;
            await mediaCapture.StartPreviewAsync();
        }
        catch (UnauthorizedAccessException)
        {
            // This will be thrown if the user denied access to the camera in privacy settings
            System.Diagnostics.Debug.WriteLine("The app was denied access to the camera");

        }
        catch (Exception)
        {
            System.Diagnostics.Debug.WriteLine("MediaCapture initialization failed.");
        }
    }


    private static async Task<DeviceInformation> GetCameraDeviceInfoAsync(Windows.Devices.Enumeration.Panel desiredPanel)
    {

        DeviceInformation device = (await DeviceInformation.FindAllAsync(DeviceClass.VideoCapture))
            .FirstOrDefault(d => d.EnclosureLocation != null && d.EnclosureLocation.Panel == desiredPanel);

        if (device == null)
        {
            throw new InvalidOperationException(string.Format(System.Globalization.CultureInfo.InvariantCulture, "No suitable devices found for the camera of type {0}.", desiredPanel));
        }
        return device;
    }
}

}
公开密封类预览
{
媒体捕获媒体捕获；
公共异步void openCam（）
{
等待StartPreviewSync（）；
}
专用异步任务StartPreviewSync（）
{
尝试
{
CaptureElement预览=新建CaptureElement（）；
StackPanel StackPanel=新StackPanel{Orientation=Orientation.Vertical}；
preview.Stretch=Windows.UI.Xaml.Media.Stretch.UniformToFill；
预览。宽度=400；
预览。高度=650；
堆叠面板。宽度=400；
stackPanel.高度=650；
stackPanel.Children.Add（预览）；
//TODO:不使用Windows.Current，需要找到获取主应用程序视图引用的方法。
//Window.Current.Content=stackPanel；
CoreApplicationView newView=CoreApplication.CreateNewView（）；
int newViewId=0；
等待newView.Dispatcher.RunAsync（CoreDispatcherPriority.Normal，（）=>
{
Window.Current.Content=stackPanel；
//您必须激活该窗口，以便稍后显示。
Window.Current.Activate（）；
newViewId=ApplicationView.GetForCurrentView（）.Id；
});
bool VIEWSHOWED=等待应用程序ViewSwitcher.TryShowAsStandaloneAsync（newViewId）；
var_deviceInformation=wait getCameradeviceInfo异步（Windows.Devices.Enumeration.Panel.Back）；
var settings=新的MediaCaptureInitializationSettings（）；
settings.StreamingCaptureMode=StreamingCaptureMode.Video；
settings.PhotoCaptureSource=PhotoCaptureSource.VideoPreview；
settings.AudioDeviceId=“”；
如果（_deviceInformation！=null）
settings.VideoDeviceId=\u deviceInformation.Id；
mediaCapture=新的mediaCapture（）；
等待mediaCapture.InitializeAsync（设置）；
mediaCapture.SetPreviewRotation（视频旋转，顺时针90度）；
preview.Source=mediaCapture；
等待mediaCapture.StartPreviewSync（）；
}
捕获（未经授权的访问例外）
{
//如果用户在“隐私设置”中拒绝访问相机，将引发此问题
System.Diagnostics.Debug.WriteLine（“应用程序被拒绝访问摄像头”）；
}
捕获（例外）
{
System.Diagnostics.Debug.WriteLine（“MediaCapture初始化失败”）；
}
}
专用静态异步任务GetCameradeviceInfo异步（Windows.Devices.Enumeration.Panel desiredPanel）
{
DeviceInformation设备=（等待DeviceInformation.FindAllAsync（DeviceClass.VideoCapture））
.FirstOrDefault（d=>d.EnclosureLocation！=null&&d.EnclosureLocation.Panel==desiredPanel）；
如果（设备==null）
{
抛出新的InvalidOperationException（string.Format（System.Globalization.CultureInfo.InvariantCulture），“未找到适合{0}类型摄像机的设备”，desiredPanel））；
}
返回装置；
}
}

}

}

public sealed class Preview
{
    MediaCapture mediaCapture;
    public async void openCam()
    {
        await StartPreviewAsync();
    }
    private async Task StartPreviewAsync()
    {
        try
        {

            CaptureElement preview = new CaptureElement();
            StackPanel stackPanel = new StackPanel { Orientation = Orientation.Vertical };
            preview.Stretch = Windows.UI.Xaml.Media.Stretch.UniformToFill;
            preview.Width = 400;
            preview.Height = 650;
            stackPanel.Width = 400;
            stackPanel.Height = 650;
            stackPanel.Children.Add(preview);

            //TODO : Instead of using Windows.Current , need to find a way to get reference of the main application view.
            //Window.Current.Content = stackPanel;

            CoreApplicationView newView = CoreApplication.CreateNewView();
            int newViewId = 0;
            await newView.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
            {

                Window.Current.Content = stackPanel;
                // You have to activate the window in order to show it later.
                Window.Current.Activate();

                newViewId = ApplicationView.GetForCurrentView().Id;
            });
            bool viewShown = await ApplicationViewSwitcher.TryShowAsStandaloneAsync(newViewId);


            var _deviceInformation = await GetCameraDeviceInfoAsync(Windows.Devices.Enumeration.Panel.Back);

            var settings = new MediaCaptureInitializationSettings();
            settings.StreamingCaptureMode = StreamingCaptureMode.Video;
            settings.PhotoCaptureSource = PhotoCaptureSource.VideoPreview;
            settings.AudioDeviceId = "";
            if (_deviceInformation != null)
                settings.VideoDeviceId = _deviceInformation.Id;

            mediaCapture = new MediaCapture();
            await mediaCapture.InitializeAsync(settings);
            mediaCapture.SetPreviewRotation(VideoRotation.Clockwise90Degrees);
            preview.Source = mediaCapture;
            await mediaCapture.StartPreviewAsync();
        }
        catch (UnauthorizedAccessException)
        {
            // This will be thrown if the user denied access to the camera in privacy settings
            System.Diagnostics.Debug.WriteLine("The app was denied access to the camera");

        }
        catch (Exception)
        {
            System.Diagnostics.Debug.WriteLine("MediaCapture initialization failed.");
        }
    }


    private static async Task<DeviceInformation> GetCameraDeviceInfoAsync(Windows.Devices.Enumeration.Panel desiredPanel)
    {

        DeviceInformation device = (await DeviceInformation.FindAllAsync(DeviceClass.VideoCapture))
            .FirstOrDefault(d => d.EnclosureLocation != null && d.EnclosureLocation.Panel == desiredPanel);

        if (device == null)
        {
            throw new InvalidOperationException(string.Format(System.Globalization.CultureInfo.InvariantCulture, "No suitable devices found for the camera of type {0}.", desiredPanel));
        }
        return device;
    }
}