Question

我创建了一个类，它派生自System.Windows.Media.AudioSink以提供录制功能。要检查我的混凝土水槽的状态，我会执行以下操作：

public class MyViewModel
{
    private readonly MyAudioSink _myAudioSink; // this field is ensured in the ctor
    public bool IsRecording
    {
        get
        {
            if (this._myAudioSink == null)
            {
                return false; // I know that `false` is wrong ...
            }
            return this._myAudioSink.CaptureSource.State == CaptureState.Started;
        }
    }
}

有时当我查询proprety IsRecording时，我会得到以下异常：

{System.InvalidOperationException: Capture source is not stopped
   at MS.Internal.XcpImports.CheckHResult(UInt32 hr)
   at MS.Internal.XcpImports.SetValue(IManagedPeerBase obj, DependencyProperty property, DependencyObject doh)
   at System.Windows.DependencyObject.SetValue(DependencyProperty property, DependencyObject doh)
   at System.Windows.Media.CaptureSource..ctor()
   at MS.Internal.CoreTypes.GetCoreWrapper(UInt32 typeId)
   at MS.Internal.ManagedPeerTable.EnsureManagedPeer(IntPtr unmanagedPointer, Int32 typeIndex, Type type, Boolean preserveManagedObjectReference)
   at MS.Internal.XcpImports.ConvertDO(IntPtr doPointer, Int32 typeIndex, Boolean releaseObjectReference)
   at MS.Internal.XcpImports.ConvertType(CValue outVal, Int32 typeIndex, Boolean releaseObjectReference, Boolean deleteBuffer, IManagedPeerBase fromObject)
   at MS.Internal.XcpImports.AudioSink_GetSource(AudioSink Sink)
   at System.Windows.Media.AudioSink.get_CaptureSource()
   at MyViewModel.get_IsRecording()

有时当我this._myAudioSink.Stop()时，我会得到以下（类似）异常：

{System.InvalidOperationException: Capture source is not stopped
   at MS.Internal.XcpImports.CheckHResult(UInt32 hr)
   at MS.Internal.XcpImports.SetValue(IManagedPeerBase obj, DependencyProperty property, DependencyObject doh)
   at System.Windows.DependencyObject.SetValue(DependencyProperty property, DependencyObject doh)
   at System.Windows.Media.CaptureSource..ctor()
   at MS.Internal.CoreTypes.GetCoreWrapper(UInt32 typeId)
   at MS.Internal.ManagedPeerTable.EnsureManagedPeer(IntPtr unmanagedPointer, Int32 typeIndex, Type type, Boolean preserveManagedObjectReference)
   at MS.Internal.XcpImports.ConvertDO(IntPtr doPointer, Int32 typeIndex, Boolean releaseObjectReference)
   at MS.Internal.XcpImports.ConvertType(CValue outVal, Int32 typeIndex, Boolean releaseObjectReference, Boolean deleteBuffer, IManagedPeerBase fromObject)
   at MS.Internal.XcpImports.AudioSink_GetSource(AudioSink Sink)
   at System.Windows.Media.AudioSink.get_CaptureSource()

那么......原因是什么？如何防止此异常（除了引入我自己的字段并将其设置为OnCaptureStarted和OnCaptureStopped的覆盖之外）？

我在网上找到的关于这个问题的唯一话题是here ...

Answer 1

我最终覆盖了特定的命令（OnCaptureStopped，OnCaptureStarted，..）以封装我的模型中的状态 AND 封装了我的具体音频中的captureSource-沉入一个单独的领域。

显然这就是诀窍，我再也没有遇到任何问题。

PS：我在某处读到了captureSource的封装应该足够了 - 我无法提供链接......它就在那里，sry！

检查CaptureSource.State时出现InvalidOperationException

1 个答案: