Metro风格的app媒体捕获异常

Question

我正在写我的第一个都市风格的应用程序.几天前,我已根据此示例(此处)编写了拍摄照片的代码,但它确实有效.随着Windows 8发布预览和visual studio 2012发布候选版本的发布,相同的代码段不起作用.似乎访问摄像机存在问题,但在Package.appxmanifest中我检查了网络摄像头功能. xaml:

<Canvas x:Name="previewCanvas1" Width="320"  Height="240" Background='Gray'>
<Image x:Name="imageElement1"  Width="320" Height="240" Visibility="Collapsed"/>
<CaptureElement x:Name="previewElement1" Width="320" Height="240" />
</Canvas>
<StackPanel Orientation="Horizontal" Margin="20" HorizontalAlignment="Center">
 <Button Width="120" x:Name="btnStartPreview2" Click="btnStartPreview_Click" IsEnabled="true"  Margin="0,0,10,0"  Background="#FFC3C3C3">Da Webcam</Button>
<Button Width="120" x:Name="btnTakePhoto2" Click="btnTakePhoto_Click" IsEnabled="false"  Margin="0,0,10,0"  Background="#FFC3C3C3">Scatta</Button>
</StackPanel>

而背后的代码:

MediaCapture mediaCaptureMgr;
async void btnStartPreview_Click(Object sender, RoutedEventArgs e)
        {
            try
            {

                mediaCaptureMgr = new Windows.Media.Capture.MediaCapture();
                await mediaCaptureMgr.InitializeAsync();

                previewElement1.Source = mediaCaptureMgr;

                await mediaCaptureMgr.StartPreviewAsync();

            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
        }

例外情况是:" 访问被拒绝.(HRESULT异常:0x80070005(E_ACCESSDENIED)) "但如上所述,网络摄像头功能已被检查!

Answer 1

我解决了 要使用网络摄像头,您必须在package.appxmanifest中指明应用程序需要访问网络摄像头和麦克风.奇怪但真实!