FlatBed Scanning (Canon Unit 101)

[Hegyi Nikoletta]

Hello!

I have a flatbed scanner (Canon Unit 101), with installed driver, but I can not find it in the source list (_twain does not contain source named like that). Just for onformation, before NTwain I tried to use TwainDotNet, and that found the source, and can scan from it. Is there anything I can do for get that source?

Thanks for Your work, and thanks for the help! Dynadelm

[Eugene Wang]

Check if the process needs to be in 32/64bit.

[Hegyi Nikoletta]

The program builds for "Any CPU" by default, I changed it to 32-bit but still the same. It gets 3 sources, but can not see the 4th (the flatbed one). The another program is in AnyCPU too.

[Eugene Wang]

Can't say why, seems to be a really special scanner. If you haven't tried, does it show in the list when you call the built-in selector (and not through my enumerated sources)? If the built-in list doesn't show then there's not much I can do either.

session.ShowSourceSelector();

[Hegyi Nikoletta]

Hello!

I tried to use what You advised, but nothing happens, when I call that method. The session has 4 owned sources, but none of them is what I need, and the window won't appear (source selector). The only thing I can think of, that the source somehow not work as a twain source, but as a wia. Can I somehow get the wia sources too?

I don't know if this helps, but heres a code snippet from the other code: Twain32Native.DsmIdentity( applicationId, IntPtr.Zero, DataGroup.Control, DataArgumentType.Identity, Message.UserSelect, defaultSourceId);

[Hegyi Nikoletta]

A little update: now the Source selector window pops up, but I cannot find the flatbed unit.

[Eugene Wang]

If the twain dsm itself (the dialog) doesn't see it then there's not much I can do either. If the other code can see it on the same machine/config then perhaps you can verify how they're initialized (same bitness, similar app identity properties when opening session). Post the code if possible.

[Hegyi Nikoletta]

I just checked the values, I didn't restart the program, just called the 2 methods.

NTwain: ID: 1 ProtocolMajor: 2 ProtocolMinor: 3 WindowHandle: 1185110 SupportedGroups: 805306371

TwainDotNet: ID: 3225 ProtocolMajor: 1 ProtocolMinor: 9 WindowHandle: 1446918 SupportedGroups: 3

Below You can find the method for getting the sources, from TwainDotNet

 public static List<DataSource> GetAllSources(Identity applicationId, IWindowsMessageHook messageHook)
        {
            var sources = new List<DataSource>();
            Identity id = new Identity();

            // Get the first source
            var result = Twain32Native.DsmIdentity(
                applicationId,
                IntPtr.Zero,
                DataGroup.Control,
                DataArgumentType.Identity,
                Message.GetFirst,
                id);

            if (result == TwainResult.EndOfList)
            {
                return sources;
            }
            else if (result != TwainResult.Success)
            {
                throw new TwainException("Error getting first source.", result);
            }
            else
            {
                sources.Add(new DataSource(applicationId, id, messageHook));
            }

            while (true)
            {
                // Get the next source
                result = Twain32Native.DsmIdentity(
                    applicationId,
                    IntPtr.Zero,
                    DataGroup.Control,
                    DataArgumentType.Identity,
                    Message.GetNext,
                    id);

                if (result == TwainResult.EndOfList)
                {
                    break;
                }
                else if (result != TwainResult.Success)
                {
                    throw new TwainException("Error enumerating sources.", result);
                }

                sources.Add(new DataSource(applicationId, id, messageHook));
            }

            return sources;
        }

[Eugene Wang]

No effective difference in DataGroup, try matching the protocol version to 1.9.

[Hegyi Nikoletta]

Hello!

I tried with 1.9, but still nothing. I'm working on it a while, and I can get the source now, but can not open. The trail I'm following is that the ID was wrong in the Session. I don't know yet what's the right ID. I'm initing NTwain with the ID I got from TwainDotNet, and then I get the sources right. I think it's something with the messageloops, and for some reason, the program needs the main form's handle, or something. I have now problems with opening the source..

Update: Sorry, I wrote it wrong. I can see, and can Open the source, but can not "Enable" it, so I can't start scanning.