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Andrey Sokolov's questions

Martin Hope
Andrey Sokolov
Asked: 2022-04-26 16:52:30 +0000 UTC
  • 1

我正在尝试使用示例https://gist.github.com/sverrirs/d099b34b7f72bb4fb386中的 GetApplicationVolume 函数，如下所示：

public static float? GetApplicationVolume(int pid)
{
    ISimpleAudioVolume volume = GetVolumeObject(pid);
    if (volume == null)
        return null;

    float level;
    volume.GetMasterVolume(out level);
    Marshal.ReleaseComObject(volume);
    return level * 100;
}

private static ISimpleAudioVolume GetVolumeObject(int pid)
{
    IMMDeviceEnumerator deviceEnumerator = null;
    IAudioSessionEnumerator sessionEnumerator = null;
    IAudioSessionManager2 mgr = null;
    IMMDevice speakers = null;
    try
    {
        // get the speakers (1st render + multimedia) device
        deviceEnumerator = (IMMDeviceEnumerator)(new MMDeviceEnumerator());
        deviceEnumerator.GetDefaultAudioEndpoint(EDataFlow.eRender, ERole.eMultimedia, out speakers);

        // activate the session manager. we need the enumerator
        Guid IID_IAudioSessionManager2 = typeof(IAudioSessionManager2).GUID;
        object o;
        speakers.Activate(ref IID_IAudioSessionManager2, 0, IntPtr.Zero, out o);
        mgr = (IAudioSessionManager2)o;

        // enumerate sessions for on this device
        mgr.GetSessionEnumerator(out sessionEnumerator);
        int count;
        sessionEnumerator.GetCount(out count);

        // search for an audio session with the required process-id
        ISimpleAudioVolume volumeControl = null;
        for (int i = 0; i < count; ++i)
        {
            IAudioSessionControl2 ctl = null;
            try
            {
                sessionEnumerator.GetSession(i, out ctl);

                // NOTE: we could also use the app name from ctl.GetDisplayName()
                int cpid;
                ctl.GetProcessId(out cpid);

                if (cpid == pid)
                {
                    volumeControl = ctl as ISimpleAudioVolume;
                    break;
                }
            }
            finally
            {
                if (ctl != null) Marshal.ReleaseComObject(ctl);
            }
        }

        return volumeControl;
    }
    finally
    {
        if (sessionEnumerator != null) Marshal.ReleaseComObject(sessionEnumerator);
        if (mgr != null) Marshal.ReleaseComObject(mgr);
        if (speakers != null) Marshal.ReleaseComObject(speakers);
        if (deviceEnumerator != null) Marshal.ReleaseComObject(deviceEnumerator);
    }
}

class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine(AudioManager.GetApplicationVolume(5992).ToString());
    }
}

并得到“未处理的异常：System.Runtime.InteropServices.InvalidComObjectException: Объект COM, который был отделен от своего базового RCW, использоваться не может.

谷歌搜索时，我进入了一些关于流量的丛林，完全糊涂了。帮助！CC# 和 .NET 以前不工作，所以不要扔拖鞋）

c#