NullreferenceException during MMNotificationClient.Dispose()

[digimezzo]

I'm using MMNotificationClient to detect a change in the default audio device. When my class, which uses the MMNotificationClient object, gets disposed when closing my application, MMNotificationClient.Dispose() is called. During MMNotificationClient.Dispose() , this nullReferenceException occurs in class "MMDeviceEnumerator" during the return in this function:

public unsafe int UnregisterEndpointNotificationCallbackNative(IMMNotificationClient notificationClient)
        {
            return InteropCalls.CallI(UnsafeBasePtr, notificationClient, ((void**) (*(void**) UnsafeBasePtr))[7]);
        }

I've created a sample application that illustrates it: WpfApplication1

Steps to reproduce:

1. Compile and launch the sample app
2. Let the sample app start playing Test.mp3
3. Close the sample app by pressing the close button on the window

=> the nullreferenceexception occurs

[filoe]

The "error" occurs when you don't dispose the _client object correctly.

[digimezzo]

Indeed, calling Dispose() on the NotificationClient resolves the issue. By the way, it seems the above fix doesn't prevent the NullReferenceException. _deviceEnumerator is not disposed when it happens, UnregisterEndpointNotificationCallbackNative still gets called and we get this:

[filoe]

Do have https://github.com/filoe/cscore/commit/cc383cdb31b63289f3db3662e7d910946ae7ce57?

[digimezzo]

No I missed that commit :( It's resolved now. As far as I'm concerned, this issue can be closed.