Question

我正在为我的音频库写一个DirectSound包装器。我遇到了directsound并且效果很好。这意味着音频播放比waveout更好地工作，等等。但现在我有一个问题。我正在尝试设置辅助缓冲区的音量。我得到一个异常，即有HResult E_NOINTERFACE，因为我的界面无法转换或类似的东西。怎么可能。我有这个Setvolume方法的代码：void SetVolume（int lVolume）;

我正在通过，例如它的值为-56。

这里确切的错误消息：

“System .__ ComObject”类型的COM对象无法强制转换为接口类型“AMEngine.DX.IDirectSoundBuffer”。无法执行此操作，因为无法执行由于错误导致IID为“{279AFA85-4981-11CE-A521-0020AF0BE560}”的接口的COM组件上的QueryInterface调用：不支持此类接口（HRESULT异常：0x80004002 （E_NOINTERFACE））。

我翻译了这个：

DEFINE_GUID(IID_IDirectSoundBuffer, 0x279AFA85, 0x4981, 0x11CE, 0xA5, 0x21, 0x00, 0x20, 0xAF, 0x0B, 0xE5, 0x60);

#undef INTERFACE
#define INTERFACE IDirectSoundBuffer
   DECLARE_INTERFACE_(IDirectSoundBuffer, IUnknown)
{
    STDMETHOD(QueryInterface)       (THIS_ __in REFIID, __deref_out LPVOID*) PURE;
    STDMETHOD_(ULONG,AddRef)        (THIS) PURE;
    STDMETHOD_(ULONG,Release)       (THIS) PURE;
    STDMETHOD(GetCaps)              (THIS_ __out LPDSBCAPS pDSBufferCaps) PURE;
    STDMETHOD(GetCurrentPosition)   (THIS_ __out_opt LPDWORD pdwCurrentPlayCursor, __out_opt LPDWORD pdwCurrentWriteCursor) PURE;
    STDMETHOD(GetFormat)            (THIS_ __out_bcount_opt(dwSizeAllocated) LPWAVEFORMATEX pwfxFormat, DWORD dwSizeAllocated, __out_opt LPDWORD pdwSizeWritten) PURE;
    STDMETHOD(GetVolume)            (THIS_ __out LPLONG plVolume) PURE;
    STDMETHOD(GetPan)               (THIS_ __out LPLONG plPan) PURE;
    STDMETHOD(GetFrequency)         (THIS_ __out LPDWORD pdwFrequency) PURE;
    STDMETHOD(GetStatus)            (THIS_ __out LPDWORD pdwStatus) PURE;
    STDMETHOD(Initialize)           (THIS_ __in LPDIRECTSOUND pDirectSound, __in LPCDSBUFFERDESC pcDSBufferDesc) PURE;
    STDMETHOD(Lock)                 (THIS_ DWORD dwOffset, DWORD dwBytes,
                                           __deref_out_bcount(*pdwAudioBytes1) LPVOID *ppvAudioPtr1, __out LPDWORD pdwAudioBytes1,
                                           __deref_opt_out_bcount(*pdwAudioBytes2) LPVOID *ppvAudioPtr2, __out_opt LPDWORD pdwAudioBytes2, DWORD dwFlags) PURE;
    STDMETHOD(Play)                 (THIS_ DWORD dwReserved1, DWORD dwPriority, DWORD dwFlags) PURE;
    STDMETHOD(SetCurrentPosition)   (THIS_ DWORD dwNewPosition) PURE;
    STDMETHOD(SetFormat)            (THIS_ __in LPCWAVEFORMATEX pcfxFormat) PURE;
    STDMETHOD(SetVolume)            (THIS_ LONG lVolume) PURE;
    STDMETHOD(SetPan)               (THIS_ LONG lPan) PURE;
    STDMETHOD(SetFrequency)         (THIS_ DWORD dwFrequency) PURE;
    STDMETHOD(Stop)                 (THIS) PURE;
    STDMETHOD(Unlock)               (THIS_ __in_bcount(dwAudioBytes1) LPVOID pvAudioPtr1, DWORD dwAudioBytes1,
                                           __in_bcount_opt(dwAudioBytes2) LPVOID pvAudioPtr2, DWORD dwAudioBytes2) PURE;
    STDMETHOD(Restore)              (THIS) PURE;
};

到

    /// <summary>
/// Line 687 Dsound.h
/// </summary>
[ComImport, InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid("279AFA85-4981-11CE-A521-0020AF0BE560")]
public interface IDirectSoundBuffer
{
    //IDirectSoundBuffer methods
    void GetCaps([Out, MarshalAs(UnmanagedType.LPStruct)] DSBufferCaps pDSBufferCaps); //TODO
    void GetCurrentPosition([Out] out UInt32 pdwCurrentPlayCursor, [Out] out UInt32 pdwCurrentWriteCursor);
    void GetFormat([Out, MarshalAs(UnmanagedType.CustomMarshaler, MarshalType = "AMEngine.Wave.WaveFormatMarshaler")] out AMEngine.Wave.WaveFormat pwfxFormat,
                    int dwSizeAllocated, [Out] out int pdwSizeWritten); //TODO implement
    [return: MarshalAs(UnmanagedType.I4) /*See http://msdn.microsoft.com/en-us/library/aa288468%28v=vs.71%29.aspx */]
    Int32 GetVolume();
    [return: MarshalAs(UnmanagedType.I4)]
    Int32 GetPan();
    [return: MarshalAs(UnmanagedType.I4)]
    Int32 GetFrequency();
    [return: MarshalAs(UnmanagedType.I4)]
    Int32 GetStatus();
    void Initialize([In, MarshalAs(UnmanagedType.Interface)] IDirectSound pDirectSound, [In] DSBufferDescription pcDSBufferDesc);
    void Lock(int dwOffset, int dwBytes,
              [Out] out IntPtr ppvAudioPtr1, [Out] out int pdwAudioBytes1,
              [Out] out IntPtr ppvAudioPtr2, [Out] out int pdwAudioBytes2,
              DSBLock dwFlags /*TODO Flags enum erstellen */);
    void Play(int dwReserved1, int dwPriority, DSBPlayFlags dwFlags); //TODO Flags enum erstellen -- Done
    void SetCurrentPosition(int dwNewPosition);
    void SetFormat([In] AMEngine.Wave.WaveFormat pcfxFormat);
    void SetVolume(int lVolume);
    void SetPan(int lPan);
    void SetFrequency(int dwFrequency);
    void Stop();
    void Unlock([In] IntPtr pvAudioPtr1, int dwAudioBytes1,
                [In] IntPtr pvAudioPtr2, int dwAudioBytes2);
    void Restore();

}

使用以下代码成功创建：

 DSBufferDescription secondaryBufferDesc = new DSBufferDescription();
        secondaryBufferDesc.dwBufferBytes = (uint)(bufferSize * 2);
        //http://msdn.microsoft.com/en-us/library/windows/desktop/microsoft.directx_sdk.reference.dsbcaps%28v=vs.85%29.aspx
        secondaryBufferDesc.dwFlags = DirectSoundBufferCaps.DSBCAPS_CTRLVOLUME |
                                      DirectSoundBufferCaps.DSBCAPS_CTRLPOSITIONNOTIFY |
                                      DirectSoundBufferCaps.DSBCAPS_GETCURRENTPOSITION2 |
                                      DirectSoundBufferCaps.DSBCAPS_GLOBALFOCUS |
                                      DirectSoundBufferCaps.DSBCAPS_STICKYFOCUS;
        secondaryBufferDesc.dwReserved = 0;
        secondaryBufferDesc.dwSize = Marshal.SizeOf(secondaryBufferDesc);
        secondaryBufferDesc.guid3DAlgorithm = Guid.Empty;
        secondaryBufferDesc.guid3DAlgorithm = Guid.Empty;

        Wave.WaveFormat format = new Wave.WaveFormat(waveFormat, waveFormat.SampleRate);
        GCHandle lpwfxSecondaryPtr = GCHandle.Alloc(format, GCHandleType.Pinned);
        secondaryBufferDesc.lpwfxFormat = lpwfxSecondaryPtr.AddrOfPinnedObject();
        //IntPtr waveFormatPtr = Marshal.AllocHGlobal(Marshal.SizeOf(waveFormat));
        //Marshal.StructureToPtr(waveFormat, waveFormatPtr, false);
        //secondaryBufferDesc.lpwfxFormat = waveFormatPtr;

        object primaryBufferObj, secondaryBufferObj;
        //http://msdn.microsoft.com/en-us/library/windows/desktop/microsoft.directx_sdk.idirectsound8.idirectsound8.createsoundbuffer%28v=vs.85%29.aspx
        directSound.CreateSoundBuffer(primaryBufferDesc, out primaryBufferObj, IntPtr.Zero);
        directSound.CreateSoundBuffer(secondaryBufferDesc, out secondaryBufferObj, IntPtr.Zero);

        lpwfxSecondaryPtr.Free();

        this.primaryBuffer = (IDirectSoundBuffer)primaryBufferObj;
        this.secondaryBuffer = (IDirectSoundBuffer)secondaryBufferObj;

并使用此代码设置音量:(我传递的值是-56）no sound = 0和maxsound = -10000

        private void SetCurrentVolume()
    {
        if (secondaryBuffer != null)
        {
            secondaryBuffer.SetVolume(volume);
        }
    }

Answer 1

E_NOINTERFACE错误很简单：您用来查询另一个界面的界面指针无法为您提供此错误。也就是说，你（或者你正在使用的库）是来自不是缓冲对象的东西的QI'ing IDirectSoundBuffer。如果您在错误位置附近发布了代码段，那将会很有帮助。

C＃DirectSound DirectSoundBuffer.SetVolume E_NOINTERFACE

1 个答案: