我正在编写一个跨平台应用程序，并试图创建一个相机预览页面，用户可以看到实时相机视图。我正在使用Xamarin Community Toolkit CameraView，遇到了一个问题。这是我的XAML文件的代码。

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:xct="http://xamarin.com/schemas/2020/toolkit"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="Test.CameraPreview"
             
             NavigationPage.HasBackButton="True"
             NavigationPage.HasNavigationBar="False">
    <ContentPage.Content>
        <Grid x:Name="cameraGrid">
            <xct:CameraView x:Name="xctCameraView"
                            CaptureMode="Photo"
                            MediaCaptured="MediaCaptured"
                            HorizontalOptions="FillAndExpand"
                            VerticalOptions="FillAndExpand"/>
            <StackLayout VerticalOptions="EndAndExpand">
                <StackLayout Orientation="Horizontal" HorizontalOptions="CenterAndExpand" BackgroundColor="Transparent">
                    <Frame CornerRadius="15" x:Name="videoFrame" WidthRequest="48" Padding="7">
                        <Label Text="Video" HorizontalOptions="CenterAndExpand" x:Name="videoLabel" BackgroundColor="Transparent"/>
                    </Frame>
                    <Frame CornerRadius="15" x:Name="pictureFrame" WidthRequest="48" Padding="7">
                        <Label Text="Picture" HorizontalOptions="CenterAndExpand" x:Name="pictureLabel" BackgroundColor="Transparent"/>
                    </Frame>
                </StackLayout>
                <ImageButton Clicked="CapturePhoto" HeightRequest="120" WidthRequest="120"
                             HorizontalOptions="Center" x:Name="captureBtn" BackgroundColor="Transparent"/>
            </StackLayout>
        </Grid>
    </ContentPage.Content>
</ContentPage>

这是CameraPreview类的C#代码，它负责拍摄照片并将照片转换为字节并将其发送到另一个页面：

private void CapturePhoto(object sender, EventArgs e)
        {
            if (isPictureSelected)
            {
                if (xctCameraView != null)
                {
                    Debug.WriteLine($"xctCameraView is not null");
                    xctCameraView.Shutter();
                    Debug.WriteLine($"camera picture taken");
                }
                else
                {
                    DisplayAlert("Error", "Camera view is not available.", "OK");
                }
            }
        }
    private void MediaCaptured(object sender, MediaCapturedEventArgs e)
        {
            switch (xctCameraView.CaptureMode)
            {
                default:
                case CameraCaptureMode.Default:

                case CameraCaptureMode.Photo:
                    Debug.WriteLine($"media captured is passed");
                    if (e.Image != null)
                    {
                        Debug.WriteLine($"e.Image is not null");
                        var imageSource = (StreamImageSource)e.Image;
                        using (var stream = imageSource.Stream(CancellationToken.None).Result)
                        {
                            using (var memoryStream = new MemoryStream())
                            {
                                Debug.WriteLine($"var memoryStream = new MemoryStream() went through");
                                stream.CopyTo(memoryStream);
                                photoData = memoryStream.ToArray();
                                // Use the byte array 'photoData' as needed
                                Debug.WriteLine($"navigating to EditPostPage");
                                Device.BeginInvokeOnMainThread(() =>
                                {
                                    Navigation.PushAsync(new EditPostPage(userId, textId, photoData));
                                });
                            }
                        }
                    }

                    break;

                case CameraCaptureMode.Video:
                    break;
            }
        }

问题是，当我拍照时，它工作正常，因为Debug.WriteLine($"camera picture taken");显示在输出中。但是，不知何故，MediaCaptured(object sender, MediaCapturedEventArgs e)没有通过，因为输出中没有显示任何调试语句。相反，在拍摄图片后，出现错误消息“[0：] CameraView：错误摄像头访问”和“错误消息：CAMERA_ERROR（3）：摄像头设备遇到严重错误。“什么问题？我试图重新启动应用程序，模拟器，并将其更改为不同的设备，但错误消息一直显示在调试输出中。