DirectSound Com Interface Import

Hmm ok I've got it working now :)
It is not that way I would like to have it but it works. I've created a MTABackgroundthread.

Thanks a lot for your help :)

If those wrappers are designed to be used from WF/WPF applications, then my guess is that they use threadpool threads. Telling the user to change the attribute on the Main() method from STA to MTA wouldn't be a good idea as a lot of stuff won't then work.

Unless those Actions themselves create threads, then you wouldn't be able to mix Actions which require STA or MTA as the background thread itself would have to be one or the other.

I suppose you could have two background threads - one for Actions requiring STA and the other for Actions requiring MTA. 

Hmmm but I wonder how other DirectX Wrappers are able to solve that problem.

And by the way whats about creating a background thread that works with something like a queue that contains Actions the thread has to call. And every time the thread gets a new action into to queue it gets pushed?

That's right, if the user is calling the dll from the main UI thread of a Windows Form or WPF application, then the apartment state will almost certainly be STA and you won't be able to change it to MTA without getting an exception. However, if the user is calling from any other thread, then you may be able to change it though I don't think this is a good idea for the reasons stated in my previous post.

Whilst starting a new thread may pose some problems of its own, I don't see what other option is open to you. However, you should be able to use the threadpool rather than creating your own thread manually if MTA is required, because that's what the threadpool uses and (to my knowledge) it can't be changed.

hmmm I defenently can t change the state of the current thread because if its a gui thread it there will be an exception.

But creating a new thread every time I call SetVolume is not that good solution because for example if the user creates a scrollbar that sets the volume. I would have to create new Threads thaaat often.

Yeah thats exactly what I've found out. But I am writing a Libary and so the Libary has to be supported by MTA and STA Thread. Is there a possibility to solve this problem?

It doesn t seems like to be very common problem because nobody really knows a solution for this problem :(

OMG I found a solution. But its not a real solution.
It works on MTAThread config but not on STAThread. Does anyone know why?

I know that it is still there but something has to be wrong.
So I am searching and searching and searching. But I can find anything.

Another question: The Interface itself seems to be right. I mean all that marshalling stuff and so on...

There's a list of the IDirectSound8 interfaces here:

http://msdn.microsoft.com/en-us/library/windows/desktop/ee416963(v=vs.85).aspx 

There are just three new ones : IDirectSound8, IDirectSoundBuffer8, and IDirectSoundCaptureBuffer8 and the rest have just been renamed.

I don't think that the new ones inherit, as such,  from the corresponding IDirectSound interfaces, though they do have some members in common.

IUnknown is still there, of course :)

hmmm i try it but i would say it won t work on other laptop.... But another idea. I just have implemented the IDirectSound interface. There is also a IDirectSound8 Interface. I may have to use that because other wrappers are using that. And so the next question. Is it possible that I can do something like that: IDirectSound8 : IDirectSound?

EDIT
OK I just tried it on another Computer. Same Result. With the IUnknown Interface it works best. sound plays on volume change --> crash.

I just did a quick google on that HRESULT and it seems to come up a lot with DirectSound:

https://www.google.co.uk/search?sugexp=chrome,mod=5&sourceid=chrome&ie=UTF-8&q=HRESULT+0x8878001E 

My guess is that it's not a problem with your translation of the COM interface but a problem with something else such as the sound-card.

That is exactly what I ve tried first. Same result :(
EDIT: OK no its not same result. I get HRESULT 0x8878001E at primaryBuffer.Play... What means that CTRL is not supported but i don t have to control volume and so on on primarybuffer... really confusing.

Ok i ll try it but regardless of whether it works thanks a lot because you are the first one that tells me gives me a concret answer.

EDIT: I can play now the primarybuffer but I still get an InvalidCastException when I try to call SetVolume because QueryInterface is not supported on the COM-Component. (E_NOINTERFACE)