Hi.

Can you help me to solve this issue.... Im working with DirectShow and
Windows Media Format SDKs from a C# app so there is a lot of interop library
work (http://directshownet.sourceforge.net), this access to directshow is
great but there is a task i want to do that requires me to use the COM
IServiceProvider interface - this is not part of the metioned library so i
would love it anyone could tell me how to make this interface available to
managed code....

This is a snippet of what i do in C++ code that i what to do in C#;

IBaseFilter pASFWriter = [instantiate this object..........]
IWMWriterAdvanced2 *pWMWA2 = NULL;
IServiceProvider *pProvider = NULL;
pASFWriter->QueryInterface(IID_IServiceProvider, (void**)&pProvider);
pProvider->QueryService(IID_IWMWriterAdvanced2, IID_IWMWriterAdvanced2,
(void**)&pWMWA2);
pWMWA2->AddSink(....);

the important part is the IServiceProvider::QueryService method. In
servprov.h this is declared as;

   EXTERN_C const IID IID_IServiceProvider;
   extern "C++"
   {
       MIDL_INTERFACE("6d5140c1-7436-11ce-8034-00aa006009fa")
       IServiceProvider : public IUnknown
       {
       public:
           virtual /* [local] */ HRESULT STDMETHODCALLTYPE QueryService(
               /* [in] */ REFGUID guidService,
               /* [in] */ REFIID riid,
               /* [out] */ void __RPC_FAR *__RPC_FAR *ppvObject) = 0;
           
           template <class Q>
           HRESULT STDMETHODCALLTYPE QueryService(REFGUID guidService, Q**
pp)
           {
               return QueryService(guidService, __uuidof(Q), (void **)pp);
           }
       };
   }

so in C# i need to declare the interface, but as what?

    [Guid("6d5140c1-7436-11ce-8034-00aa006009fa"),
    InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    public interface IServiceProvider
    {
        //QueryService(...)
    }

I am really struggling to understand how to map over the interface so any
help would be most appreciated, many thank.