How add callback function to IWMReader COM object

[James5950]

Dear All,

I create a COM object IWMReader, this object need add Callback, like this
ReaderCallback::OnSample

I don't know to add these by BCB2007
My code like these

TComInterface<IWMReader> m_pReader;
TComInterface<IWMReaderCallback> ReaderCallback;
HRESULT hr = m_pReader->Open( L"Test.mp3", ReaderCallback, NULL );

Please tell me how to manipulate IWMReader and IWMReaderCallback by BCB2007.
Thanks for any comments.

Best regards,
James

[Alex Bakaev [TeamB]]

James5950 wrote:

> Please tell me how to manipulate IWMReader and IWMReaderCallback by
> BCB2007.
> Thanks for any comments.
>

Does adding & before ReaderCallback help?

[James5950]

Hello Alex,

I need add ReadCallBack::OnSample on my project for receive this callback
message, but I can not find any sample code manipulate by BCB2007.

I declare the call back function on header file, but I don't know how to
manipulate these call back function.
I copy some code from MS Media Format SDK Audioplay sample code.
//
// Methods of IWMReaderCallback
//
HRESULT STDMETHODCALLTYPE OnStatus( /* [in] */ WMT_STATUS Status,
/* [in] */ HRESULT hr,
/* [in] */ WMT_ATTR_DATATYPE dwType,
/* [in] */ BYTE __RPC_FAR *pValue,
/* [in] */ void __RPC_FAR *pvContext );

HRESULT STDMETHODCALLTYPE OnSample( /* [in] */ DWORD dwOutputNum,
/* [in] */ QWORD cnsSampleTime,
/* [in] */ QWORD cnsSampleDuration,
/* [in] */ DWORD dwFlags,
/* [in] */ INSSBuffer __RPC_FAR *pSample,
/* [in] */ void __RPC_FAR *pvContext );

Thanks for your response.
Best regards,
James

"Alex Bakaev [TeamB]" <zx...@att.net> 在郵件
news:47fa5d09$1...@newsgroups.borland.com 中撰寫...

[Alex Bakaev [TeamB]]

James5950 wrote:
> Hello Alex,
>
> I need add ReadCallBack::OnSample on my project for receive this
> callback message, but I can not find any sample code manipulate by BCB2007.
>

Well, the code should be identical, no matter what compiler you are using.

[James5950]

Hello Alex,

Please provide me example about manipulate COM object add Callback interface
with OnSample mothod.

Thanks for your reponse.
Best regards,
James

"Alex Bakaev [TeamB]" <zx...@att.net> 在郵件

news:47fa6e78$1...@newsgroups.borland.com 中撰寫...

[James5950]

Hello Remy,

Great, that's good example for me.

Best regards,

James

[Remy Lebeau (TeamB)]

"James5950" <Ja...@1come.com.tw> wrote in message
news:47fa...@newsgroups.borland.com...

> I create a COM object IWMReader, this object need add
> Callback, like this ReaderCallback::OnSample
>
> I don't know to add these by BCB2007

You need to write a new class that derives from the IWMReaderCallback
interface, implementing all of its methods (including the ones from
IWMStatusCallback and IUnknown as well), or example (untested):

class TMyWMReaderCallback : public IWMReaderCallback
{
private:
ULONG FRefCnt;

public:
TMyWMReaderCallback();

// IUnknown
HRESULT __stdcall QueryInterface(REFIID riid, void** pv);
ULONG __stdcall AddRef();
ULONG __stdcall Release();

// IWMStatusCallback
HRESULT __stdcall OnStatus(WMT_STATUS Status, HRESULT hr,
WMT_ATTR_DATATYPE dwType, BYTE* pValue, void* pvContext);

// IWMReaderCallback
HRESULT __stdcall OnSample(DWORD dwOutputNum, QWORD cnsSampleTime,
QWORD cnsSampleDuration, DWORD dwFlags, INSSBuffer* pSample, void*
pvContext);
};

TMyWMReaderCallback::TMyWMReaderCallback()
: FRefCnt(0)
{
}

HRESULT __stdcall TMyWMReaderCallback::QueryInterface(REFIID riid,
void** pv)
{
if( !pv )
return E_POINTER;

*pv = NULL;

if( IsEqualIID(riid, IID_IWMReaderCallback) )
*pv = (IWMReaderCallback*) this;
else if( IsEqualIID(riid, IID_IWMStatusCallback )
*pv = (IWMReaderCallback*) this;
else if( IsEqualIID(riid, IID_IUnknown) )
*pv = (IUnknown*) (IWMReaderCallback*) this;

if( *pv == NULL )
return E_NOINTERFACE;

AddRef();
return S_OK;
}

ULONG __stdcall TMyWMReaderCallback::AddRef()
{
return ++FRefCnt;
}

ULONG __stdcall TMyWMReaderCallback::Release()
{
if( --FRefCnt == 0 )
{
delete this;
return 0;
}
return FRefCnt;
}

HRESULT __stdcall TMyWMReaderCallback::OnStatus(WMT_STATUS Status,
HRESULT hr, WMT_ATTR_DATATYPE dwType, BYTE* pValue, void* pvContext)
{
// do something...
return S_OK;
}

HRESULT __stdcall TMyWMReaderCallback::OnSample(DWORD dwOutputNum, QWORD
cnsSampleTime, QWORD cnsSampleDuration, DWORD dwFlags, INSSBuffer* pSample,
void* pvContext)
{
// do something...
return S_OK;
}

Then you can do the following:

{
TComInterface<IWMReader> m_pReader;
// instantiate m_pReader as needed, then...
TComInterface<IWMReaderCallback> ReaderCallback(new
TMyReaderCallback, true);

HRESULT hr = m_pReader->Open( L"Test.mp3", ReaderCallback, NULL );

//...
}

Gambit