Re: TwainSession becomes invalidated when not closed

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This topic and its replies were posted before the current version of LEADTOOLS was released and may no longer be applicable.

#1 Posted : Thursday, January 12, 2006 11:27:11 AM(UTC)

ryoder

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Posts: 7

I am using v14.5 and if there is an unhandled exception in my application and I don't close down the TwainSession object, the scanner is unusable in any program until I do a full reboot.

Additionally, I can't even detect if the scanner is available using the TwainSession because simply doing a QuickWatch on the object pops up the Twain scanner error dialog over and over again saying the scanner power is unplugged until I kill the process.


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#2 Posted : Monday, January 16, 2006 12:51:38 AM(UTC)

Maen Hasan

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Hello,

What is the exact programming interface (COM, API, .Net, etc.) that you use?
Can you pleas provide me with a code snippet that shows the problem, in order to check this issue on my machine?

Thanks,
Maen Badwan
LEADTOOLS Technical Support

#3 Posted : Thursday, January 19, 2006 4:50:02 AM(UTC)

ryoder

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Posts: 7

I use DotNet 14.5 and you can test this by running the twainmultipage demo and commenting out the twainSession.ShutDown() method. The next time you run the demo you cant do anything with the twainsession and no other programs on the machine that use twain will work.

#4 Posted : Friday, January 20, 2006 11:10:15 AM(UTC)

Otis

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You must call the TwainSession.ShutDown() method when you are done with the device. This disconnects LEADTOOLS from the device driver. If you do not disconnect, the device will not be useable by any other application. This is true for any TWAIN device and any TWAIN application.

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