pendingTransfer.Count alway return 0 ?

[GoogleCodeExporter]

What steps will reproduce the problem?
1.
2.
3.

What is the expected output? What do you see instead?

What version of the product are you using? On what operating system?

Please provide any additional information below.

Original issue reported on code.google.com by ledin...@gmail.com on 13 Nov 2012 at 7:11

[GoogleCodeExporter]

when i scanning on Cannon lide 110 pendingTransfer.Count alway return 0, i 
can't continue scan next page

 do
                {
                    pendingTransfer.Count = 0;
                    IntPtr hbitmap = IntPtr.Zero;

                    // Get the image info
                    ImageInfo imageInfo = new ImageInfo();
                    result = Twain32Native.DsImageInfo(
                        ApplicationId,
                        DataSource.SourceId,
                        DataGroup.Image,
                        DataArgumentType.ImageInfo,
                        Message.Get,
                        imageInfo);

                    if (result != TwainResult.Success)
                    {
                        DataSource.Close();
                        break;
                    }

                    // Transfer the image from the device
                    result = Twain32Native.DsImageTransfer(
                        ApplicationId,
                        DataSource.SourceId,
                        DataGroup.Image,
                        DataArgumentType.ImageNativeXfer,
                        Message.Get,
                        ref hbitmap);

                    if (result != TwainResult.XferDone)
                    {
                        DataSource.Close();
                        break;
                    }

                    // End pending transfers
                    result = Twain32Native.DsPendingTransfer(
                        ApplicationId,
                        DataSource.SourceId,
                        DataGroup.Control,
                        DataArgumentType.PendingXfers,
                        Message.EndXfer,
                        pendingTransfer);

                    if (result != TwainResult.Success)
                    {
                        DataSource.Close();
                        break;
                    }

                    if (hbitmap == IntPtr.Zero)
                    {
                        log.Warn("Transfer complete but bitmap pointer is still null.");
                    }
                    else
                    {
                        using (var renderer = new BitmapRenderer(hbitmap))
                        {
                            TransferImageEventArgs args = new TransferImageEventArgs(renderer.RenderToBitmap(), pendingTransfer.Count != 0);
                            TransferImage(this, args);
                            if (!args.ContinueScanning)
                                break;
                        }
                    }
                }
                while (pendingTransfer.Count != 0);

Original comment by ledin...@gmail.com on 13 Nov 2012 at 7:21