//private readonly IOleWindow _oleWindow;
public PreviewHandler(IPreviewHandlerFrame previewHandlerFrame, string fileName)
{
_previewHandler = CreatePreviewHandler(fileName);
_previewHandlerVisuals = _previewHandler as IPreviewHandlerVisuals;
var objectWithSite = _previewHandler as IObjectWithSite;
Log.Debug($"objectWithSite: {objectWithSite}");
objectWithSite?.SetSite(previewHandlerFrame).ThrowIfFailed("IObjectWithSite::SetSite");
}
void SetupHandler(Guid clsid)
{
IntPtr pph;
var iid = IPreviewHandlerIid;
var cannotCreate = "Cannot create class " + clsid.ToString() + " as IPreviewHandler.";
var cannotCast = "Cannot cast class " + clsid.ToString() + " as IObjectWithSite.";
var cannotSetSite = "Cannot set site to the preview handler object.";
// Important: manully calling CoCreateInstance is necessary.
// If we use Activator.CreateInstance(Type.GetTypeFromCLSID(...)),
// CLR will allow in-process server, which defeats isolation and
// creates strange bugs.
HResult hr = CoCreateInstance(ref clsid, IntPtr.Zero, ClassContext.LocalServer, ref iid, out pph);
// See https://blogs.msdn.microsoft.com/adioltean/2005/06/24/when-cocreateinstance-returns-0x80080005-co_e_server_exec_failure/
// CO_E_SERVER_EXEC_FAILURE also tends to happen when debugging in Visual Studio.
// Moreover, to create the instance in a server at low integrity level, we need
// to use another thread with low mandatory label. We keep it simple by creating
// a same-integrity object.
if (hr == HResult.CO_E_SERVER_EXEC_FAILURE)
{
hr = CoCreateInstance(ref clsid, IntPtr.Zero, ClassContext.LocalServer, ref iid, out pph);
}
if ((int)hr < 0)
{
throw new COMException(cannotCreate, (int)hr);
}
pPreviewHandler = pph;
var previewHandlerObject = Marshal.GetUniqueObjectForIUnknown(pph);
previewHandler = previewHandlerObject as IPreviewHandler;
if (previewHandler == null)
{
Marshal.ReleaseComObject(previewHandlerObject);
throw new COMException(cannotCreate);
}
var objectWithSite = previewHandlerObject as IObjectWithSite;
if (objectWithSite == null)
{
throw new COMException(cannotCast);
}
hr = objectWithSite.SetSite(comSite);
if ((int)hr < 0)
{
throw new COMException(cannotSetSite, (int)hr);
}
visuals = previewHandlerObject as IPreviewHandlerVisuals;
}
