c# - 在 C# 中处理更改的音频设备事件

Question

我想知道当我将耳机或其他输出设备插入(或取出)到声卡插孔时如何处理事件。

在这里和谷歌上搜索给我提供了关于“naudio”库的信息，但它的文档非常糟糕，无法检查，而且该项目的一位协调员告诉我他不确定他们的库中是否有可能。

我的最终目的是自动控制不同设备的音量，例如启用耳机时 - 设置 10% 音量，启用扬声器时 - 设置 100%。

Answer 1

您可以使用 NAudio 的 MMDeviceEnumerator 和 IMMNotificationClient 来完成。但是，您将 RegisterEndpointNotificationCallback 和 UnRegisterEndpointNotificationCallback 的实现添加到 MMDeviceEnumerator 类

实现是

 /// <summary>
       /// Registers a call back for Device Events
       /// </summary>
        /// <param name="client">Object implementing IMMNotificationClient type casted as IMMNotificationClient interface</param>
       /// <returns></returns>
        public int RegisterEndpointNotificationCallback([In] [MarshalAs(UnmanagedType.Interface)] IMMNotificationClient client)
        {
            //DeviceEnum declared below
            return deviceEnum.RegisterEndpointNotificationCallback(client);
        }

        /// <summary>
        /// UnRegisters a call back for Device Events
        /// </summary>
        /// <param name="client">Object implementing IMMNotificationClient type casted as IMMNotificationClient interface </param>
        /// <returns></returns>
        public int UnRegisterEndpointNotificationCallback([In] [MarshalAs(UnmanagedType.Interface)] IMMNotificationClient client)
        {
            //DeviceEnum declared below
            return deviceEnum.UnregisterEndpointNotificationCallback(client);
        } 

然后创建一个实现IMMNotificationClient的类

示例:

class NotificationClientImplementation : NAudio.CoreAudioApi.Interfaces.IMMNotificationClient
    {

        public void OnDefaultDeviceChanged(DataFlow dataFlow, Role deviceRole, string defaultDeviceId)
        {
            //Do some Work
            Console.WriteLine("OnDefaultDeviceChanged --> {0}", dataFlow.ToString());
        }

        public void OnDeviceAdded(string deviceId)
        {
             //Do some Work
            Console.WriteLine("OnDeviceAdded -->");
        }

        public void OnDeviceRemoved(string deviceId)
        {

            Console.WriteLine("OnDeviceRemoved -->");
             //Do some Work
        }

        public void OnDeviceStateChanged(string deviceId, DeviceState newState)
        {
            Console.WriteLine("OnDeviceStateChanged\n Device Id -->{0} : Device State {1}", deviceId, newState);
             //Do some Work
        }

        public NotificationClientImplementation()
        {
            //_realEnumerator.RegisterEndpointNotificationCallback();
            if (System.Environment.OSVersion.Version.Major < 6)
            {
                throw new NotSupportedException("This functionality is only supported on Windows Vista or newer.");
            }
        }

        public void OnPropertyValueChanged(string deviceId, PropertyKey propertyKey)
        {
             //Do some Work
             //fmtid & pid are changed to formatId and propertyId in the latest version NAudio
            Console.WriteLine("OnPropertyValueChanged: formatId --> {0}  propertyId --> {1}", propertyKey.formatId.ToString(), propertyKey.propertyId.ToString());
        }

    }

那么你所要做的就是

1. 声明以下 NAudio 对象和 IMMNotificationClient 的实现

示例:

private NAudio.CoreAudioApi.MMDeviceEnumerator deviceEnum = new NAudio.CoreAudioApi.MMDeviceEnumerator();
private NotificationClientImplementation notificationClient;
private NAudio.CoreAudioApi.Interfaces.IMMNotificationClient notifyClient;

1. 然后键入 cast notificationClient as IMMNotificationClient 并将其作为参数传递给 MMDeviceEnumerator

示例:

notificationClient = new NotificationClientImplementation();
notifyClient = (NAudio.CoreAudioApi.Interfaces.IMMNotificationClient)notificationClient;
deviceEnum.RegisterEndpointNotificationCallback(notifyClient);

希望这对 body 有帮助。感谢 MSDN 论坛，尤其是 Michael Taylor http://msmvps.com/blogs/p3net感谢您帮助我。

谢谢和干杯。