CaptureSource.Start() 在 Windows Phone Silverlight 8.1 中抛出 System.UnauthorizedAccessException

Question

我在 Windows Phone Silverlight 8.1 应用程序中使用相机时遇到问题。我只想初始化相机并查看其预览（现在我不需要任何照片或视频捕获）。我找到了 nice and simple example on MSDN 和

private CaptureSource captureSource;
private VideoCaptureDevice videoCaptureDevice;

private void InitializeVideoRecorder()
{
    try
    {
        if (captureSource == null)
        {
            captureSource = new CaptureSource();
            var a = captureSource.VideoCaptureDevice;

            videoCaptureDevice = CaptureDeviceConfiguration.GetDefaultVideoCaptureDevice();

            captureSource.CaptureFailed += OnCaptureFailed;

            if (videoCaptureDevice != null)
            {
                VideoRecorderBrush = new VideoBrush();
                VideoRecorderBrush.SetSource(captureSource);

                captureSource.Start();
                CameraStatus = "Tap record to start recording...";
            }
            else
            {
                CameraStatus = "A camera is not supported on this phone.";
            }
        }
    }
    catch (Exception ex)
    {
        CameraStatus = "ERROR: " + ex.Message.ToString();
    }
}

代码在 captureSource.Start(); 处停止并抛出 System.UnauthorizedAccessException: Attempted to perform an unauthorized operation.。

首先，我发现信息（在同一页上）表明“WMAppManifest.xml”需要 ID_CAP_ISV_CAMERA 功能。但是我在添加它时遇到问题，因为：

我在设计器中找不到这个功能
手动将其添加到 .xml 文件时出现错误

错误重现如下：

Warning 1   The 'Name' attribute is invalid - The value 'ID_CAP_ISV_CAMERA' is invalid according to its datatype 'http://schemas.microsoft.com/appx/2010/manifest:ST_Capabilities' - The Enumeration constraint failed.
Error   3   App manifest validation failed. Value 'ID_CAP_ISV_CAMERA' of attribute '/Package/Capabilities/Capability/@Name' must be a valid capability.

我什至在 SO WP8.1 SilverLight Microsoft.Devices.PhotoCamera Access Denied

上找到了相同的解决方案

有人能告诉我为什么我不能使用原始的 MSDN 解决方案来解决这个问题吗？

Answer 1

首先，您似乎正在尝试将该功能添加到 Package.appxmanifest 而不是 WMAppManifest.xml。您应该能够在 Solution Explorer -> -> Properties:

下找到 WMAppManifest.xml

打开该文件应该可以让您选择添加 ID_CAP_* 功能。

其次，您需要同时指定 ID_CAP_ISV_CAMERA 和 ID_CAP_MICROPHONE 才能使用 CaptureSource.Start()，即使您只使用其中一台设备。

CaptureSource.Start() 在 Windows Phone Silverlight 8.1 中抛出 System.UnauthorizedAccessException

CaptureSource.Start() throws System.UnauthorizedAccessException in Windows Phone Silverlight 8.1

c#

silverlight

windows-phone-8.1