MIDL VARIANT-type to proper C# type

[Bjoern]

Hi

I have a COM object which fires an event where I have to pass an array
of SHORTs as a parameter to the listening object. The array of SHORTs
is encapsulated in a the CComSafeArray-class and passed as a VARIANT*
in MIDL (since MIDL doesn't support SAFEARRAYs in events).

In C# (.NET 1.0) the MIDL VARIANT* data-type is registered as "ref
object" in the event-handler (delegate). How do I convert this "ref
object" to a short array?

-- Bjoern

[Mattias Sjögren]

>How do I convert this "ref
object" to a short array?

You probably only need a cast.

void YourEventHandle r(ref object o)
{
short[] arr = (short[])o;
// Do stuff...
}

If that doesn't work please tell us what o.GetType().Ful lName returns.
Mattias

--
Mattias Sjögren [C# MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

[Bjoern]

Hi

When I get the full path of the VARIANT* type it says
"System.Boolean ".

Here's how my IDL event is declared:

HRESULT OnUserAudioData ([in] LONG nUserID, [in] LONG nSampleRate, [in]
VARIANT* pRawAudio, [in] LONG nSamples);

Here's how I pass my data to the event:

//-- begin
Audio* aud = reinterpret_cas t<Audio*(lParam );
CComSafeArray<S HORT, VT_I2safeArray;
if(aud->samples)
safeArray.Add(a ud->samples, aud->rawAudio, TRUE);
CComVariant vtVar(safeArray );
m_pListener->Fire_OnUserAud ioData(aud->userid, aud->samplerate,
&vtVar, aud->samples);
//-- end

Any idea why C# thinks it's a boolean?

-- Bjoern
On Sep 25, 5:53 am, Mattias Sjögren <mattias.dont.w ant.s...@mvps.o rg>
wrote:

How do I convert this "ref
object" to a short array?

You probably only need a cast.

void YourEventHandle r(ref object o)
{
short[] arr = (short[])o;
// Do stuff...

}

If that doesn't work please tell us what o.GetType().Ful lName returns.

Mattias

--
Mattias Sjögren [C# MVP] mattias @ mvps.orghttp://www.msjogren.ne t/dotnet/|http://www.dotnetinterop.com
Please reply only to the newsgroup.