Why can my 32-bit application not see my TWAIN scanner?

#1 Posted : Monday, September 16, 2013 11:40:31 PM(UTC)

Daoud

Groups: Registered
Posts: 256

If you are sure that the 3rd-party application is using TWAIN and not WIA drivers, then the most likely cause is that you have a 64-bit TWAIN driver for your scanner.
32-bit TWAIN drivers are in the Windows\TWAIN_32 directory and 64-bit TWAIN drivers in the Windows\TWAIN_64 directory. The file extension for a TWAIN driver is .ds.

You should verify that you have the correct TWAIN driver using Twacker. Twacker is a test tool from the TWAIN Working group. To obtain the utility, go to Tools section of this TWAIN.org page.

If you want to be able to support both 32-bit and 64-bit TWAIN drivers, then you can choose to launch the TwainSession using the Thunk Server which will Initialize the TWAIN session with THUNK server option in order to interact with 32-Bit TWAIN drivers from a 64-Bit process.

Startup Method:
https://www.leadtools.com/help/sdk/dh/tw/twainsession-startup.html

TwainStartupFlags Enum
https://www.leadtools.com/help/sdk/dh/tw/twainstartupflags.html

Code:

TwainSession session = new TwainSession(); 
   session.Startup(parent, "manufacturer", "productFamily", "version", "application", TwainStartupFlags.UseThunkServer);

So if you have a 64 bit application, using the Thunk server startup flag will enable you to interact with both 64 bit devices as well as 32 bit ones.

Edited by moderator Wednesday, December 27, 2023 3:57:40 PM(UTC) | Reason: Updated

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Why can my 32-bit application not see my TWAIN scanner?