Forums › TWAIN Classic › Scanner starts transfer when console gets closed (CITRIX)
Hi, we compiled & published the sample console (https://github.com/soukoku/ntwain/tree/v3/samples) from CITRIX environment. Did not get any errors but scanning is not happening but the scanner is pulling the paper when the console gets closed. Does anyone have any idea on this. But this is working fine from local machine.
Sorry, there are too many moving parts to be able to offer much help.
The TWAIN Working Group has no connection to that sample code, so the problem may be there. It’s also possible that the scanner driver is an issue, it may help to try a different scanner to see if the problem reproduces.
As for paper being pulled when the scanner closes, you may want to investigate if the MSG_XFERREADY message is being properly delivered. Again, this will likely depend on the specific scanner driver being used.
Finally, Citrix has two modes: the old mode used a driver proxy that marshalled commands across the network, the newer mode creates a USB connection across the network. You’ll want to understand which mode is is use as you investigate. You should also contact the scanner vendor to confirm that their scanner supports what is being attempted.
Thank you for sharing the details. If it is an issue with driver or scanner means it should not work with any other application. But we are able to scan it through Twacker (32 bit) application (CITRIX). So what would be difference between console application and Twacker (32 bit) application.
You are correct. If you are able to use TWACKER in the CITRIX environment, then it’s less likely that the problem is with the TWAIN driver. However, that implicates the ntwain sample being used. You also didn’t specify if the CITRIX connection was using the TWAIN marshalling mode or the USB mode. That will make a difference too. The older scheme is going to require using the nearly 20 year old TWAIN32.DLL. The new scheme allows you to use the 100% compatible (and supported) open source TWAINDSM.DLL.
The TWAIN Working Group has no connection this this sample code, we can’t speak to any issues it may have. The best we can offer is that you can compare the TWACKER source code to ntwain.
TWACKER can be found here: github.com/twain/twain-toolkit
You may also want to investigate the TWAIN C# project (found here: github.com/twain/twain-cs), which includes the TWAIN Certification tool, which is a console application that allows an interactive experience with TWAIN drivers. It may help you better understand what is going on.