IltmmAudioFormats::get_Count Example for C

// Having an IltmmCapture Interface, pCap:

IltmmAudioFormats *pAudioFormats;
IltmmAudioFormat *pAudioFormat;
long   lCount;
long lFreq, lBits, lChannels;
long lFoundAt;
long lSelection;
VARIANT_BOOL bSelected;

// get the audio formats collection:
IltmmCapture__get_AudioCaptureFormats(pCap, &pAudioFormats);
IltmmAudioFormats__get_Count(pAudioFormats, &lCount);

for( i=0; i<lCount; i++ )
{
   // get the item at index I
   IltmmAudioFormats_Item(pAudioFormats, i, &pAudioFormat);
  
   // do something with this item, like viewing its information:
   IltmmAudioFormat__get_SampleFrequency(pAudioFormat, &lFreq);
   IltmmAudioFormat__get_BitsPerSample(pAudioFormat, &lBits);
   IltmmAudioFormat__get_Channels(pAudioFormat, &lChannels);
   IltmmAudioFormat__get_Selected(pAudioFormat, &bSelected);

   // view information …

   // you may select the format if it matches some criteria:
   if( lFreq == 8000 && lBits == 8 && lChannels == 1 )
         IltmmAudioFormat__put_Selected(pAudioFormat, VARIANT_TRUE);

   // free the item
   IUnknown_Release(pAudioFormat);
}

// you might use the Find method to search for a specific format:
IltmmAudioFormats__Find(pAudioFormats, 16000, 16, 2, &lFoundAt);
If( lFoundAt != -1 )
{
   // do something with it:
   // check if it is already selected, and if not, select it:
   IltmmAudioFormats__get_Selection(pAudioFormats, &lSelection);
   If( lSelection != lFoundAt )
   {
      IltmmAudioFormats__put_Selection(pAudioFormats, lFoundAt);
   }
}

// free the audio formats collection
IUnknown_Release(pAudioFormats);