Video Capture

Development Platform:

Visual C++

DsBugWO.cs：Code Content

							/******************************************************
                  DirectShow .NET
		      netmaster@swissonline.ch
*******************************************************/
//           WORKAROUND FOR DS BUGs
using System;
using System.Text;
using System.Runtime.InteropServices;
namespace DShowNET
{
public class DsBugWO
{
	/*
	works:
		CoCreateInstance( CLSID_CaptureGraphBuilder2, ..., IID_ICaptureGraphBuilder2, ...);
	doesn't (E_NOTIMPL):
		CoCreateInstance( CLSID_CaptureGraphBuilder2, ..., IID_IUnknown, ...);
	thus .NET 'Activator.CreateInstance' fails
	*/
	public static object CreateDsInstance( ref Guid clsid, ref Guid riid )
	{
		IntPtr ptrIf;
		int hr = CoCreateInstance( ref clsid, IntPtr.Zero, CLSCTX.Inproc, ref riid, out ptrIf );
		if( (hr != 0) || (ptrIf == IntPtr.Zero) )
			Marshal.ThrowExceptionForHR( hr );
		Guid iu = new Guid( "00000000-0000-0000-C000-000000000046" );
		IntPtr ptrXX;
		hr = Marshal.QueryInterface( ptrIf, ref iu, out ptrXX );
		object ooo = System.Runtime.Remoting.Services.EnterpriseServicesHelper.WrapIUnknownWithComObject( ptrIf );
		int ct = Marshal.Release( ptrIf );
		return ooo;
	}
	[DllImport("ole32.dll") ]
	private static extern int CoCreateInstance(	ref Guid clsid, IntPtr pUnkOuter, CLSCTX dwClsContext, ref Guid iid, out IntPtr ptrIf );
}
[Flags]
internal enum CLSCTX
	{
	Inproc					= 0x03,
	Server					= 0x15,
	All						= 0x17,
	}
} // namespace DShowNET

						