// Collect filters of specified category
private void CollectFilters( Guid category )
{
object comObj = null;
ICreateDevEnum enumDev;
IEnumMoniker enumMon = null;
var devMon = new IMoniker[1];
try
{
// Get the system device enumerator
Type srvType = Type.GetTypeFromCLSID( Clsid.SystemDeviceEnum );
if ( srvType == null )
throw new ApplicationException( "Failed creating device enumerator" );
// create device enumerator
comObj = Activator.CreateInstance( srvType );
enumDev = (ICreateDevEnum) comObj;
// Create an enumerator to find filters of specified category
int hr = enumDev.CreateClassEnumerator( ref category, out enumMon, 0 );
if ( hr != 0 )
throw new ApplicationException( "No devices of the category" );
// Collect all filters
IntPtr n = IntPtr.Zero;
while ( true )
{
// Get next filter
hr = enumMon.Next( 1, devMon, n );
if ( ( hr != 0 ) || ( devMon[0] == null ) )
break;
// Add the filter
var filter = new FilterInfo( devMon[0] );
InnerList.Add( filter );
// Release COM object
Marshal.ReleaseComObject( devMon[0] );
devMon[0] = null;
}
// Sort the collection
InnerList.Sort( );
}
catch
{
}
finally
{
// release all COM objects
enumDev = null;
if ( comObj != null )
{
Marshal.ReleaseComObject( comObj );
comObj = null;
}
if ( enumMon != null )
{
Marshal.ReleaseComObject( enumMon );
enumMon = null;
}
if ( devMon[0] != null )
{
Marshal.ReleaseComObject( devMon[0] );
devMon[0] = null;
}
}
}
// Display property page for the specified object
private void DisplayPropertyPage( IntPtr parentWindow, object sourceObject )
{
try
{
// retrieve ISpecifyPropertyPages interface of the device
var pPropPages = sourceObject as ISpecifyPropertyPages;
if (pPropPages==null)
{
var e = sourceObject as IAMVfwCompressDialogs;
if (e == null)
{
throw new NotSupportedException("The video source does not support the compressor dialog page.");
}
e.ShowDialog(VfwCompressDialogs.Config, IntPtr.Zero);
return;
}
// get property pages from the property bag
CAUUID caGUID;
pPropPages.GetPages( out caGUID );
// get filter info
var filterInfo = new FilterInfo( _deviceMoniker );
// create and display the OlePropertyFrame
NativeMethods.OleCreatePropertyFrame(parentWindow, 0, 0, filterInfo.Name, 1, ref sourceObject, caGUID.cElems, caGUID.pElems, 0, 0, IntPtr.Zero);
// release COM objects
Marshal.FreeCoTaskMem( caGUID.pElems );
}
catch
{
// ignored
}
}
public static object CreateFilter( string filterMoniker )
{
object filterObject = null;
object comObj = null;
ICreateDevEnum enumDev;
IEnumMoniker enumMon = null;
var devMon = new IMoniker[1];
try
{
// Get the system device enumerator
Type srvType = Type.GetTypeFromCLSID(Clsid.SystemDeviceEnum);
if (srvType == null)
throw new ApplicationException("Failed creating device enumerator");
// create device enumerator
comObj = Activator.CreateInstance(srvType);
enumDev = (ICreateDevEnum)comObj;
// Create an enumerator to find filters of specified category
Guid cat = FilterCategory.VideoInputDevice;
int hr = enumDev.CreateClassEnumerator(ref cat, out enumMon, 0);
if (hr != 0)
throw new ApplicationException("No devices of the category");
// Collect all filters
IntPtr n = IntPtr.Zero;
while (true)
{
// Get next filter
hr = enumMon.Next(1, devMon, n);
if ((hr != 0) || (devMon[0] == null))
break;
// Add the filter
var filter = new FilterInfo(devMon[0]);
if (filter.MonikerString == filterMoniker)
{
Guid filterId = typeof(IBaseFilter).GUID;
devMon[0].BindToObject(null, null, ref filterId, out filterObject);
break;
}
// Release COM object
Marshal.ReleaseComObject(devMon[0]);
devMon[0] = null;
}
}
catch
{
}
finally
{
// release all COM objects
enumDev = null;
if (comObj != null)
{
Marshal.ReleaseComObject(comObj);
comObj = null;
}
if (enumMon != null)
{
Marshal.ReleaseComObject(enumMon);
enumMon = null;
}
if (devMon[0] != null)
{
Marshal.ReleaseComObject(devMon[0]);
devMon[0] = null;
}
}
return filterObject;
//// filter's object
//object filterObject = null;
//// bind context and moniker objects
//IBindCtx bindCtx = null;
//IMoniker moniker = null;
//int n = 0;
//// create bind context
//if ( Win32.CreateBindCtx( 0, out bindCtx ) == 0 )
//{
// // convert moniker`s string to a moniker
// if ( Win32.MkParseDisplayName( bindCtx, filterMoniker, ref n, out moniker ) == 0 )
// {
// // get device base filter
// Guid filterId = typeof( IBaseFilter ).GUID;
// moniker.BindToObject( null, null, ref filterId, out filterObject );
// Marshal.ReleaseComObject( moniker );
// }
// Marshal.ReleaseComObject( bindCtx );
//}
//return filterObject;
}